jwh-133 and Disease-Models--Animal

The pharmacological activation of cannabinoid type 2 receptors (CB2R) gained attention due to its ability to mitigate neuroinflammatory events without eliciting psychotropic actions, a limiting factor for the drugs targeting cannabinoid type 1 receptors (CB1R). Therefore, ligands activating CB2R are receiving enormous importance for therapeutic targeting in numerous neurological diseases including neurodegenerative, neuropsychiatric and neurodevelopmental disorders as well as traumatic injuries and neuropathic pain where neuroinflammation is a common accompaniment. Since the characterization of CB2R, many CB2R selective synthetic ligands have been developed with high selectivity and functional activity. Among numerous ligands, JWH133 has been found one of the compounds with high selectivity for CB2R. JWH133 has been reported to exhibit numerous pharmacological activities including antioxidant, anti-inflammatory, anticancer, cardioprotective, hepatoprotective, gastroprotective, nephroprotective, and immunomodulatory. Recent studies have shown that JWH133 possesses potent neuroprotective properties in several neurological disorders, including neuropathic pain, anxiety, epilepsy, depression, alcoholism, psychosis, stroke, and neurodegeneration. Additionally, JWH133 showed to protect neurons from oxidative damage and inflammation, promote neuronal survival and neurogenesis, and serve as an immunomodulatory agent. The present review comprehensively examined neuropharmacological activities of JWH133 in neurological disorders including neurodegenerative, neurodevelopmental and neuropsychiatric using synoptic tables and elucidated pharmacological mechanisms based on reported observations. Considering the cumulative data, JWH133 appears to be a promising CB2R agonist molecule for further evaluation and it can be a prototype agent in drug discovery and development for a unique class of agents in neurotherapeutics. Further, regulatory toxicology and pharmacokinetic studies are required to determine safety and proceed for clinical evaluation.

Topics: Animals; Cannabinoid Receptor Agonists; Cannabinoids; Disease Models, Animal; Drug Evaluation, Preclinical; Humans; Mental Disorders; Neurodegenerative Diseases; Neurodevelopmental Disorders; Receptor, Cannabinoid, CB2

Traumatic brain injury (TBI) destroys white matter, and this destruction is aggravated by secondary neuroinflammatory reactions. Although white matter injury (WMI) is strongly correlated with poor neurological function, understanding of white matter integrity maintenance is limited, and no available therapies can effectively protect white matter. One candidate approach that may fulfill this goal is cannabinoid receptor 2 (CB2) agonist treatment. Here, we confirmed that a selective CB2 agonist, JWH133, protected white matter after TBI.. The motor evoked potentials (MEPs), open field test, and Morris water maze test were used to assess neurobehavioral outcomes. Brain tissue loss, WM damage, Endoplasmic reticulum stress (ER stress), microglia responses were evaluated after TBI. The functional integrity of WM was measured by diffusion tensor imaging (DTI) and transmission electron microscopy (TEM). Primary microglia and oligodendrocyte cocultures were used for additional mechanistic studies.. JWH133 increased myelin basic protein (MBP) and neurofilament heavy chain (NF200) levels and anatomic preservation of myelinated axons revealed by DTI and TEM. JWH133 also increased the numbers of oligodendrocyte precursor cells and mature oligodendrocytes. Furthermore, JWH133 drove microglial polarization toward the protective M2 phenotype and modulated the redistribution of microglia in the striatum. Further investigation of the underlying mechanism revealed that JWH133 downregulated phosphorylation of the protein kinase R (PKR)-like endoplasmic reticulum (ER) kinase (PERK) signaling pathway and its downstream signals eukaryotic translation initiation factor 2 α (eIF2α), activating transcription factor 4 (ATF4) and Growth arrest and DNA damage-inducible protein (GADD34); this downregulation was followed by p-Protein kinase B(p-Akt) upregulation. In primary cocultures of microglia and oligodendrocytes, JWH133 decreased phosphorylated PERK expression in microglia stimulated with tunicamycin and facilitated oligodendrocyte survival. These data reveal that JWH133 ultimately alleviates WMI and improves neurological behavior following TBI. However, these effects were prevented by SR144528, a selective CB2 antagonist.. This work illustrates the PERK-mediated interaction between microglia and oligodendrocytes. In addition, the results are consistent with recent findings that microglial polarization switching accelerates WMI, highlighting a previously unexplored role for CB2 agonists. Thus, CB2 agonists are potential therapeutic agents for TBI and other neurological conditions involving white matter destruction.

Topics: Animals; Cannabinoid Receptor Agonists; Cannabinoids; Cells, Cultured; Disease Models, Animal; eIF-2 Kinase; Evoked Potentials, Motor; Male; Microglia; Rats; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB2; Signal Transduction; White Matter

Bacterial pneumonia is a major risk factor for acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Pseudomonas aeruginosa (PA), an opportunistic pathogen with an increasing resistance acquired against multiple drugs, is one of the main causative agents of ALI and ARDS in diverse clinical settings. Given the anti-inflammatory role of the cannabinoid-2 receptor (CB2R), the effect of CB2R activation in the regulation of PA-induced ALI and inflammation was tested in a mouse model as an alternative to conventional antibiotic therapy.. In order to activate CB2R, a selective synthetic agonist, JWH133, was administered intraperitoneally (i.p.) to C57BL/6J mice. Furthermore, SR144528 (a selective CB2R antagonist) was administered in combination with JWH133 to test the specificity of the CB2R-mediated effect. PA was administered intratracheally (i.t.) for induction of pneumonia in mice. At 24 h after PA exposure, lung mechanics were measured using the FlexiVent system. The total cell number, protein content, and neutrophil population in the bronchoalveolar lavage fluid (BALF) were determined. The bacterial load in the whole lung was also measured. Lung injury was evaluated by histological examination and PA-induced inflammation was assessed by measuring the levels of BALF cytokines and chemokines. Neutrophil activation (examined by immunofluorescence and immunoblot) and PA-induced inflammatory signaling (analyzed by immunoblot) were also studied.. CB2R activation by JWH133 was found to significantly reduce PA-induced ALI and the bacterial burden. CB2R activation also suppressed the PA-induced increase in immune cell infiltration, neutrophil population, and inflammatory cytokines. These effects were abrogated by a CB2R antagonist, SR144528, further confirming the specificity of the CB2R-mediated effects. CB2R-knock out (CB2RKO) mice had a significantly higher level of PA-induced inflammation as compared to that in WT mice. CB2R activation diminished the excess activation of neutrophils, whereas mice lacking CB2R had elevated neutrophil activation. Pharmacological activation of CB2R significantly reduced the PA-induced NF-κB and NLRP3 inflammasome activation, whereas CB2KO mice had elevated NLRP3 inflammasome.. Our findings indicate that CB2R activation ameliorates PA-induced lung injury and inflammation, thus paving the path for new therapeutic avenues against PA pneumonia.

Topics: Acute Lung Injury; Animals; Cannabinoids; Cytokines; Disease Models, Animal; Inflammasomes; Inflammation; Mice; Mice, Inbred C57BL; NLR Family, Pyrin Domain-Containing 3 Protein; Pseudomonas aeruginosa; Pseudomonas Infections; Receptor, Cannabinoid, CB2; Receptors, Cannabinoid; Respiratory Distress Syndrome

Uterus transplantation is a complex surgical procedure. Uterine ischemia/reperfusion (IR) damage occurring in this process may cause loss of function in the uterus. Cell damage must be prevented for a healthy uterine function and successful transplantation. Cannabinoids, with their increasing clinical use, are substances with strong anti-inflammatory and antioxidative effects and have a role in immune system regulation. However, their efficacy in uterine IR damage is still unknown. This study provides information on the potential applications cannabinoids agonist JWH-133 in uterine IR damage and, hence, in the transplant process.. Rats were divided into 4 groups (n = 8), performed uterine IR, and treated 2 groups with JWH-133. After anesthesia, ischemia was applied for 1 h to the uterus while reperfusion was applied for 3 h. After the experiment, malondialdehyde (MDA) levels and phosphorylated nuclear factor-kappa B (p-NF-κB) expression were examined in the tissue samples. Also, cell damage was evaluated by histopathological imaging and TUNEL staining.. In the uterine IR group, NF-κB expression and MDA levels were detected at high levels. Histopathological examinations and TUNEL staining revealed extensive cell damage. On the other hand, in groups treated with JWH-133, dose-dependent NF-κB expression and MDA levels decreased (p < 0.05). Depending on the dose, the rate of surviving cells increased in TUNEL staining results.. The results showed that JWH-133 was effective in reducing uterine IR damage. Cannabinoids may be a new alternative that may be used in the transplantation process in the future.

Topics: Animals; Apoptosis; Cannabinoid Receptor Agonists; Cannabinoids; Cell Survival; Disease Models, Animal; Female; In Situ Nick-End Labeling; Injections, Intraperitoneal; Malondialdehyde; NF-kappa B; Protective Agents; Rats, Wistar; Receptor, Cannabinoid, CB2; Reperfusion Injury; Uterus

The endocannabinoid system became a promising target for osteoarthritis (OA) treatment. Functional selectivity of cannabinoids may increase their beneficial properties while reducing side effects. The aim of the present study was to evaluate the analgesic potential of two functionally biased CB2 agonists in different treatment regimens to propose the best pharmacological approach for OA management.. Two functionally selective CB2 agonists were administered i.p. - JWH133 (cAMP biased) and GW833972A (β-arrestin biased), in a chemically induced model of OA in rats. The drugs were tested in acute and chronic treatment regimens. Analgesic effects were assessed by pressure application measurement and kinetic weight bearing. X-ray microtomography was used for the morphometric analysis of the femur's subchondral bone tissue. Underlying biochemical changes were analysed via RT-qPCR.. Dose-response studies established the effective dose for both JWH133 and GW833972A. In chronic treatment paradigms, JWH133 was able to elicit analgesia throughout the course of the experiment, whereas GW833972A lost its efficacy after 2 days of treatment. Later studies revealed improvement in subchondral bone architecture and decrement of matrix metalloproteinases and proinflammatory factors expression following JWH133 chronic treatment.. Data presents analgesic and disease-modifying potential of CB2 agonists in OA treatment. Moreover, the study revealed more pronounced tolerance development for analgesic effects of the β-arrestin biased CB2 agonist GW833972A. These results provide a better understanding of the molecular underpinnings of the anti-nociceptive potential of CB2 agonists and may improve drug development processes for any cannabinoid-based chronic pain therapy.

Topics: Analgesics; Animals; Arthralgia; Cannabinoid Receptor Agonists; Cannabinoids; Disease Models, Animal; Drug Tolerance; Iodoacetic Acid; Joints; Male; Osteoarthritis; Pain Threshold; Pyridines; Pyrimidines; Rats, Wistar; Receptor, Cannabinoid, CB2; Signal Transduction; Time Factors

Uncontrolled infection and increased inflammatory mediators might cause systemic inflammatory response. It is already known that Cannabinoid Type 2 (CB2) receptors, which are commonly expressed in immune cells and in many other tissues, have an effect on the regulation of immune response. In the present study of ours, the effects of CB2 receptor agonist JWH-133 was investigated on cecal ligation and puncture (CLP)-induced polymicrobial sepsis model in rats. In the present study, Sprague-Dawley rats were divided into 5 groups (i.e. the Sham, CLP, JWH-133 0.2 mg/kg, JWH-133 1 mg/kg, and JWH-133 5 mg/kg Groups). Except for the Sham Group, the CLP-induced sepsis model was applied to all groups. The histopathological damage in brain, lung, liver and, heart was examined and the caspase-3, p-NF-κB, TNF-α, IL-1β and IL-6 levels were determined immunohistochemically. The serum TNF-α, IL-1β, IL-6, IL-10 levels were examined with the ELISA Method. The JWH-133 treatment decreased the histopathological damage in brain, heart, lung, and liver and reduced the caspase-3, p-NF-κB, TNF-α, IL-1β, IL-6 levels in these tissues. In addition to this, JWH-133 treatment also decreased the serum TNF-α, IL-1β, IL-6 levels, which were increased due to CLP, and increased the anti-inflammatory cytokine IL-10 levels. In the present study, it was determined that the CB2 receptor agonist JWH-133 decreases the CLP-induced inflammation, and reduces the damage in brain, lung, liver and heart. Our findings show the therapeutic potential of the activation of CB2 receptors with JWH-133 in sepsis.

Topics: Animals; Brain; Cannabinoids; Cecum; Cytokines; Disease Models, Animal; Heart; Ligation; Liver; Lung; Male; Myocardium; NF-kappa B; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB2; Sepsis

Cannabinoid-2 receptor (CB2R) plays an important role in the cascading inflammation following ischemic injury. The toll-like receptors 4 (TLR4)/matrix metalloproteinase 9 (MMP9) signal pathway is involved in blood-brain barrier dysfunction induced by ischemia stroke. The aim of this study is to investigate the roles of exogenous activation of CB2R on attenuating neurological deficit and blood-spinal cord barrier (BSCB) disruption during rat spinal cord ischemia reperfusion (I/R) injury, through modulation of the TLR4/MMP9 axis.. Animals were intraperitoneally pretreated with TLR4 inhibitor TAK-242, CB2R agonist JWH-133 with or without CB2R antagonist AM630, or equivalent volume of vehicle 1 h before undergoing 14-min occlusion of descending aorta or sham operation. One, two, three, and 7 days after reperfusion, hindlimb locomotor function was evaluated with Basso, Beattie, and Bresnahan (BBB) Locomotor Scale, BSCB integrity was detected by measurement of Evans blue (EB) extravasation and spinal cord edema. The protein expression levels of CB2R, tight junction protein Zonula occluden-1 (ZO-1), TLR4, MMP9, MyD88, NF-κB p65, and NF-κB p-p65 were determined by western blot. The MMP9 activity was analyzed by gelatin zymography. Double immunofluorescence staining was used to identify the perivascular localization of CB2R, TLR4, MMP9, and reactive astrocytes, as well as the colocalization of CB2R, TLR4, and MMP9 with reactive astrocytes.. JWH-133 pretreatment attenuated hindlimb motor functional deficit and BSCB leakage, along with preventing downregulation of ZO-1 and upregulation of TLR4/MMP9, similar to the effects of TAK-242 preconditioning. JWH-133 or TAK-242 pretreatment reduced the perivascular expression of TLR4/MMP9 and reactive astrocytes following injury. JWH-133 pretreatment also downregulated MyD88/NF-κB level, MMP9 activity, and the astrocytic TLR4/MMP9 after I/R injury.. Exogenous activation of CB2R by JWH-133 attenuated neurological deficit and BSCB disruption after spinal cord I/R injury via inhibition of TLR4/MMP9 expression.

Topics: Animals; Cannabinoids; Disease Models, Animal; Down-Regulation; Hindlimb; Male; Matrix Metalloproteinase 9; Rats; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB2; Recovery of Function; Reperfusion Injury; Signal Transduction; Spinal Cord; Spinal Cord Ischemia; Sulfonamides; Toll-Like Receptor 4; Up-Regulation

The blood-brain barrier (BBB) disruption and the following development of brain edema, is the most life-threatening secondary injury after intracerebral hemorrhage (ICH). This study is to investigate a potential role and mechanism of JWH133, a selected cannabinoid receptor type2 (CB2R) agonist, on protecting blood-brain barrier integrity after ICH.. 192 adult male Sprague-Dawley (SD) rats were randomly divided into Sham; ICH + Vehicle; ICH + JWH 1.0 mg/kg, ICH + JWH 1.5 mg/kg and ICH + JWH 2.0 mg/kg; ICH + SR + JWH respectively. Animals were euthanized at 24 h following western blots and immunofluorescence staining, we also examined the effect of JWH133 on the brain water contents, neurobehavioral deficits and blood brain barrier (BBB) permeability, meanwhile reassessed the inflammatory cytokines concentrations around the hematoma by enzyme-linked immunosorbent assay (ELISA) in each group.. JWH133 (1.5 mg/kg) administration ameliorated brain edema, neurological deficits and blood-brain barrier damage, as well as microglia activation. The expression of pro-inflammatory mediators interleukin 1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and matrix metallopeptidase-2/9 (MMP2/9) were attenuated, but not monocyte chemoattractant protein-1 (MCP-1). Additionally, decreases in zonula occludens-1 (ZO-1) and claudin-5 expression were partially recovered by JWH133. Furthermore, JWH133 upregulated the expression level of MKP-1, which leads to the inhibition of MAPKs signaling pathway activation, especially for ERK and P38. However, these effects were reversed by pretreatment with a selective CB2R antagonist, SR144528.. CB2R agonist alleviated neuroinflammation and protected blood-brain barrier permeability in a rat ICH model. Further molecular mechanisms revealed which is probably mediated by enhancing the expression of MKP-1, then inhibited MAPKs signal transduction.

Topics: Animals; Biological Transport; Blood-Brain Barrier; Brain; Brain Edema; Camphanes; Cannabinoids; Cerebral Hemorrhage; Cytokines; Disease Models, Animal; Dual Specificity Phosphatase 1; Male; Permeability; Pyrazoles; Rats; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB2; Signal Transduction

Neuroinflammation plays a major role in postoperative cognitive dysfunction (POCD). Accumulated evidence indicates that cannabinoid receptor type 2 (CB2R) can mediate anti-inflammatory and immunomodulatory effects in part by controlling microglial activity. However, the impact of CB2R on postoperative cognition has not been investigated. We hypothesized that CB2R is involved in surgery-induced cognitive impairment in adult mice.. Adult C57BL/6 mice were subjected to intramedullary fixation surgery for tibial fracture under isoflurane anesthesia and CB2R agonist (JWH133) or CB2R antagonist (AM630) treatment. The mice were trained 24 h prior to surgery using a fear conditioning protocol and assessed in a novel context on postoperative days 1, 3, and 7 to evaluate cognitive function. Open-field testing was performed to evaluate the locomotor activity of the mice. The expression levels of IL-1β, TNF-α, MCP-1, and CB2R in the hippocampus and prefrontal cortex were assessed by Western blotting; the expression of microglial marker CD11b in the CA1 area of the hippocampus and medial prefrontal cortex was assessed by immunostaining.. The mice displayed no changes in locomotor activity after surgery and drug treatments. The mice exhibited impaired hippocampal-dependent memory accompanied by an increased expression of proinflammatory factors in the hippocampus and prefrontal cortex 1, 3, and 7 days after surgery, while hippocampal-independent memory remained unaffected at the same time points. JWH133 treatment attenuated surgery-induced memory loss, while AM630 treatment aggravated surgery-induced memory loss, paralleled by a decreased or increased expression of proinflammatory factors in the hippocampus and prefrontal cortex. The expression of CB2R in the hippocampus and prefrontal cortex was upregulated following surgery; however, it was downregulated by postoperative treatment with JWH133. Similarly, the expression of CD11b in the CA1 area of the hippocampus and medial prefrontal cortex was upregulated following surgery and downregulated by postoperative treatment with JWH133.. These findings indicate that CB2R may modulate the neuroinflammatory and cognitive impairment in a mouse model of orthopedic surgery, and the activation of CB2R may effectively ameliorate the hippocampal-dependent memory loss of mice in the early postoperative stage.

Topics: Animals; Anti-Inflammatory Agents; Brain; Cannabinoids; Cognition Disorders; Cytokines; Disease Models, Animal; Encephalitis; Exploratory Behavior; Fracture Fixation, Intramedullary; Indoles; Mice; Mice, Inbred C57BL; Postoperative Complications; Receptor, Cannabinoid, CB2; Tibial Fractures; Time Factors

The activation of the transcription factor Nrf2 inhibits neuropathy and modulates the activity of delta-opioid receptors (DOR) in type 2 diabetic mice but the impact of Nrf2/HO-1 pathway on the antinociceptive actions of cannabinoid 2 receptors (CB2R) has not been assessed. Using male mice BKS.Cg-m+/+Leprdb/J (db/db) we investigated if treatment with cobalt protoporphyrin IX (CoPP), an HO-1 inductor, inhibited mechanical allodynia, hyperglycemia and obesity associated to type 2 diabetes. The antinociceptive effects of JWH-015 and JWH-133 (CB2R agonists) administered with and without CoPP or sulforaphane (SFN), a Nrf2 transcription factor activator, have been also evaluated. The expression of Nrf2, HO-1, NAD(P)H: quinone oxidoreductase 1 (NQO1) and c-Jun N-terminal kinase (JNK) in sciatic nerve and that of the CB2R on the dorsal root ganglia from animals treated with CoPP and/or SFN were assessed. CoPP treatment inhibited allodynia, hyperglycemia and body weight gain in db/db mice by enhancing HO-1/NQO1 levels and reducing JNK phosphorylation. Both CoPP and SFN improved the antiallodynic effects of JWH-015 and JWH-133 and expression of CB2R in db/db mice. Therefore, we concluded that the activation of antioxidant Nrf2/HO-1 pathway potentiate the effects of CB2R agonists and might be suitable for the treatment of painful neuropathy linked to type 2 diabetes.

Topics: Animals; Blood Glucose; Body Weight; Cannabinoid Receptor Agonists; Cannabinoids; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Diabetic Neuropathies; Disease Models, Animal; Ganglia, Spinal; Heme Oxygenase-1; Hyperalgesia; Male; Mice; Mice, Transgenic; NF-E2-Related Factor 2; Protoporphyrins; Receptor, Cannabinoid, CB2; Sciatic Nerve

Fibrosis in ventricular system has a role in hydrocephalus following intraventricular hemorrhage (IVH). The cannabinoid receptor 2 (CB2) has been reported to participate in alleviating the fibrosis process of many diseases. However, its role in fibrosis after IVH was unclear so far, and we hypothesized that CB2 activation has potential to attenuate hydrocephalus after IVH via restricting fibrosis. So the present study was designed to investigate this hypothesis in a modified rat IVH model. Autologous non-anticoagulative blood injection model was induced to mimic ventricular extension of hemorrhage in adult Sprague-Dawley rats. Rats were randomized to receive JWH-133(CB2 agonist), SR144528 (CB2 antagonist) or saline. The lateral ventricular volumes, fibrosis in the subarachnoid space and ventricular wall, transforming growth factor-β 1(TGF-β1) in cerebrospinal fluid and brain tissue, and animal neurological scores were measured to evaluate the effects of CB2 in hydrocephalus following IVH. CB2 agonist JWH-133 significantly decreased the lateral ventricular volumes, improved the associated neurological deficits, down-regulated TGF-β1 expression, and alleviated fibrosis in the subarachnoid space and ventricular wall after IVH. All of these effects were reversed by SR144528. In conclusion, CB2 may have anti-fibrogenic effects after IVH. CB2 agonist suppressed fibrosis of ventricular system and alleviated hydrocephalus following IVH, which is partly mediated by inhibiting TGF-β1.

Topics: Animals; Brain; Camphanes; Cannabinoid Receptor Agonists; Cannabinoid Receptor Antagonists; Cannabinoids; Cerebral Hemorrhage; Disease Models, Animal; Fibrosis; Hydrocephalus; Male; Neuroprotective Agents; Pyrazoles; Random Allocation; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB2; Transforming Growth Factor beta1

Microglia play dual roles after germinal matrix hemorrhage, and the neurotrophic phenotype maybe neuroprotective. However, the phenotype transformation and the way by which neuron-microglia dialogue remain unclear. We raise the hypothesis that a cannabinoid receptor2 agonist (JWH133) accelerates the CX3CR1

Topics: Animals; Animals, Newborn; Brain Injuries; Brain-Derived Neurotrophic Factor; Camphanes; Cannabinoids; CX3C Chemokine Receptor 1; Disease Models, Animal; Female; In Vitro Techniques; Intracranial Hemorrhages; Male; Microglia; Nerve Tissue Proteins; Pregnancy; Pyrazoles; Rats; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB2; Receptors, Chemokine; RNA, Small Interfering; Up-Regulation

We evaluated whether JWH133, a selective cannabinoid type 2 receptor (CB2R) agonist, prevented neurogenic pulmonary edema (NPE) after subarachnoid hemorrhage (SAH) by attenuating inflammation. Adult male rats were assigned to six groups: sham-operated, SAH with vehicle, SAH with JWH133 (0.3, 1.0, or 3.0 mg/kg) treatment 1 h after surgery, and SAH with JWH133 (1.0 mg/kg) at 1 h with a selective CB2R antagonist, SR144528 (3.0 mg/kg). The perforation model of SAH was performed and pulmonary wet-to-dry weight ratio was evaluated 24 and 72 h after surgery. Western blot analyses and immunohistochemistry were evaluated 24 h after surgery. JWH133 (1.0 mg/kg) significantly and most strongly improved lung edema 24 h after SAH. SR144528 administration significantly reversed the effects of JWH133 (1.0 mg/kg). SAH-induced increasing levels of myeloperoxidase (MPO) and decreasing levels of a tight junction (TJ) protein, junctional adhesion molecule (JAM)-A, were ameliorated by JWH133 (1.0 mg/kg) administration 24 h after SAH. Immunohistochemical assessment also confirmed substantial leukocyte infiltration in the outside of vessels in SAH, which were attenuated by JWH133 (1.0 mg/kg) injection. CB2R agonist ameliorated lung permeability by inhibiting leukocyte trafficking and protecting tight junction proteins in the lung of NPE after SAH.

Topics: Animals; Blotting, Western; Camphanes; Cannabinoid Receptor Agonists; Cannabinoid Receptor Antagonists; Cannabinoids; Cell Movement; Disease Models, Animal; Immunohistochemistry; Junctional Adhesion Molecules; Lung; Male; Neutrophils; Organ Size; Peroxidase; Pulmonary Edema; Pyrazoles; Rats; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB2; Subarachnoid Hemorrhage

One of the most common psychological consequences of stroke is post-stroke depression (PSD). While more than 30 percent of stroke patients eventually develop PSD, the neurobiological mechanisms underlying such a phenomenon have not been well investigated. Given the critical involvement of hypothalamic-pituitary-adrenal axis and endocannabinoid system in response to stressful stimuli, we evaluated the hypothesis that cannabinoid receptors in the hypothalamus are critical for modulation of post-stroke depression-like behaviors in rats. To this end, rats were treated with middle cerebral artery occlusion (MCAO) followed by chronic unpredictable mild stress (CUMS) treatment procedure. We then assessed the expression of CB1 and CB2 receptors in the hypothalamus, and evaluated the effects of pharmacological stimulations of CB1 or CB2 receptors on the expression and development of depression-like behaviors in PSD rats. We found that PSD rats exhibited decreased the expression of CB1 receptor, but not CB2 receptor, in the ventral medial hypothalamus (VMH). Such an effect was not observed in the dorsally adjacent brain regions. Furthermore, intra-VMH injections of CB2 receptor agonist, but not CB1 receptor agonist, attenuated the expression of depression-like behaviors in PSD rats. Finally, repeated intraperitoneal injections of CB1 or CB2 receptor agonists during CUMS treatment inhibited the development of depression-like behaviors in PSD rats. Taken together, these results suggest that decreased CB1 receptor expression is likely associated with the development of post-stroke depression, and CB2 receptor may be a potential therapeutic target for the treatment post-stroke depressive disorders.

Topics: Animals; Arachidonic Acids; Cannabinoid Receptor Agonists; Cannabinoids; Depression; Disease Models, Animal; Dose-Response Relationship, Drug; Exploratory Behavior; Food Preferences; Hypothalamus; Infarction, Middle Cerebral Artery; Male; Microinjections; Rats; Rats, Sprague-Dawley; Receptors, Cannabinoid; Stroke

Accumulation of activated eosinophils in tissue is a hallmark of allergic inflammation. The endocannabinoid 2-arachidonoylglycerol (2-AG) has been proposed to elicit eosinophil migration in a CB2 receptor/Gi/o -dependent manner. However, it has been claimed recently that this process may also involve other mechanisms such as cytokine priming and the metabolism of 2-AG into eicosanoids. Here, we explored the direct contribution of specific CB2 receptor activation to human and mouse eosinophil effector function in vitro and in vivo.. In vitro studies including CB2 expression, adhesion and migratory responsiveness, respiratory burst, degranulation, and calcium mobilization were conducted in human peripheral blood eosinophils and mouse bone marrow-derived eosinophils. Allergic airway inflammation was assessed in mouse models of acute OVA-induced asthma and directed eosinophil migration.. CB2 expression was significantly higher in eosinophils from symptomatic allergic donors. The selective CB2 receptor agonist JWH-133 induced a moderate migratory response in eosinophils. However, short-term exposure to JWH-133 potently enhanced chemoattractant-induced eosinophil shape change, chemotaxis, CD11b surface expression, and adhesion as well as production of reactive oxygen species. Receptor specificity of the observed effects was confirmed in eosinophils from CB2 knockout mice and by using the selective CB2 antagonist SR144528. Of note, systemic application of JWH-133 clearly primed eosinophil-directed migration in vivo and aggravated both AHR and eosinophil influx into the airways in a CB2 -specific manner. This effect was completely absent in eosinophil-deficient ∆dblGATA mice.. Our data indicate that CB2 may directly contribute to the pathogenesis of eosinophil-driven diseases. Moreover, we provide new insights into the molecular mechanisms underlying the CB2 -mediated priming of eosinophils. Hence, antagonism of CB2 receptors may represent a novel pharmacological approach for the treatment of allergic inflammation and other eosinophilic disorders.

Topics: Allergens; Animals; Biomarkers; Calcium; Cannabinoids; Cell Degranulation; Cell Movement; Disease Models, Animal; Eosinophils; Female; Gene Expression; Humans; Hypersensitivity; MAP Kinase Signaling System; Mice; Pertussis Toxin; Pneumonia; Receptor, Cannabinoid, CB2; rho-Associated Kinases

Cannabinoids have anti-inflammatory effects and can produce bronchodilation in the airways. We have investigated the effects of cannabinoids on tracheal hyperreactivity and airway inflammation in dinitrofluorobenzene (DNFB)-induced experimental non-atopic asthma in mice. 5-hydroxytryptamine (5-HT)-induced contraction response was enhanced while carbachol- and electrical field stimulation-induced contractions, and isoprenaline-induced relaxation responses were remained unchanged in DNFB group. The increased 5-HT-induced contractions were inhibited by incubation with either atropine or tetrodotoxin. DNFB application resulted in increased macrophage number in the bronchoalveolar lavage fluid (BALF). In vivo ACEA (CB1 agonist) treatment prevented the increase in 5-HT contractions, while JWH133 (CB2 agonist) had no effect. However, neither ACEA nor JWH133 prevented the increase in macrophage number in BALF. In vitro ACEA incubation also inhibited the increase in 5-HT contraction in DNFB group. These results show that cannabinoid CB1 receptor agonist can prevent tracheal hyperreactivity to 5-HT in DNFB-induced non-atopic asthma in mice.

Topics: Acetylcholine; Animals; Anti-Asthmatic Agents; Asthma; Atropine; Cannabinoid Receptor Agonists; Cannabinoids; Carbachol; Dinitrofluorobenzene; Disease Models, Animal; Dose-Response Relationship, Drug; Electric Stimulation; Female; Macrophages; Mice; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Serotonin; Tetrodotoxin; Trachea

Germinal matrix hemorrhage (GMH) is one of the most common and devastating cerebrovascular events that affect premature infants, resulting in a significant socioeconomic burden. However, GMH has been largely unpreventable, and clinical treatments are mostly inadequate. In the present study, we tested the hypothesis that JWH133, a selective CB2 receptor agonist, could attenuate brain injury and neurological deficits in a clostridial collagenase VII induced GMH model in seven-day-old (P7) S-D rat pups. Up to 1h post-injury, the administration of JWH133 (1mg/kg, intraperitoneal injection) significantly attenuated brain edema at 24h post-GMH, which was reversed by a selective CB2R antagonist, SR144528 (3mg/kg, intraperitoneal injection). Long-term brain morphology and neurofunctional outcomes were also improved. In contrast, JWH133 did not have a noticeable effect on the hematoma volume during the acute phase. These data also showed that microglia activation and inflammatory cytokine (TNF-α) release were significantly inhibited by JWH133 after GMH. This current study suggests a potential clinical utility for CB2R agonists as a potential therapy to reduce neurological injury and improve patient outcomes after GMH.

Topics: Acute Disease; Animals; Brain; Brain Edema; Camphanes; Cannabinoid Receptor Agonists; Cannabinoid Receptor Antagonists; Cannabinoids; Chronic Disease; Disease Models, Animal; Female; Intracranial Hemorrhages; Male; Microglia; Movement; Neuroprotective Agents; Pyrazoles; Random Allocation; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB2; Tumor Necrosis Factor-alpha

The purpose of the experiments was to explore the role of the endocannabinoid system, through cannabinoid (CB) receptor ligands, nicotine and scopolamine, in the depression-related responses using the forced swimming test (FST) in mice. Our results revealed that acute injection of oleamide (10 and 20 mg/kg), a CB1 receptor agonist, caused antidepressant-like effect in the FST, while AM 251 (0.25-3 mg/kg), a CB1 receptor antagonist, did not provoke any effect in this test. Moreover, acute administration of both CB2 receptor agonist, JWH 133 (0.5 and 1 mg/kg) and CB2 receptor antagonist, AM 630 (0.5 mg/kg), exhibited antidepressant action. Antidepressant effects of oleamide and JWH 133 were attenuated by acute injection of both non-effective dose of AM 251, as well as AM 630. Among the all CB compounds used, only the combination of non-effective dose of oleamide (2.5 mg/kg) with non-effective dose of nicotine (0.5 mg/kg) caused an antidepressant effect. However, none of the CB receptor ligands, had influence on the antidepressant effects provoked by nicotine (0.2 mg/kg) injection. In turn, the combination of non-effective dose of oleamide (2.5 mg/kg); JWH (2 mg/kg) or AM 630 (2 mg/kg), but not of AM 251 (0.25 mg/kg), with non-effective dose of scopolamine (0.1 mg/kg), exhibited antidepressant properties. Indeed, all of the CB compounds used, intensified the antidepressant-like effects induced by an acute injection of scopolamine (0.3 mg/kg). Our results provide clear evidence that the endocannabinoid system participates in the depression-related behavior and through interactions with cholinergic system modulate these kind of responses.

Topics: Animals; Antidepressive Agents; Cannabinoids; Depressive Disorder; Disease Models, Animal; Indoles; Ligands; Male; Mice; Motor Activity; Nicotine; Oleic Acids; Piperidines; Pyrazoles; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Scopolamine; Swimming

Microglia accumulation plays detrimental roles in the pathology of germinal matrix hemorrhage (GMH) in the immature preterm brain. However, the underlying mechanisms remain poorly defined. Here, we investigated the effects of a cannabinoid receptor 2 (CB2R) agonist on microglia proliferation and the possible involvement of the mitogen-activated protein kinase (MAPK) family pathway in a collagenase-induced GMH rat model and in thrombin-induced rat microglia cells. We demonstrated that activation of CB2R played a key role in attenuating brain edema, neuronal degeneration, microglial accumulation and the phosphorylated extracellular signal-regulated kinase (p-ERK) protein level 24 h following GMH. In vitro, Western blot analysis and immunostaining indicated that ERK and P38 phosphorylation levels in microglia stimulated by thrombin were decreased after JWH-133 (CB2R selective agonist) treatment in a concentration-dependent manner. Microglia proliferation (EDU + microglia) and inflammatory and oxidative stress responses were attenuated by UO126 (ERK pathway inhibitor) 24 h after thrombin stimulation, an activity that was prevented by AM630 (CB2R selective antagonist). Overall, these findings suggest that activation of the endocannabinoid system might attenuate inflammation-induced secondary brain injury after GMH in rats by reducing microglia accumulation through a mechanism involving ERK dephosphorylation. Enhancing CB2R activation is a potential treatment to slow down the course of GMH in preterm newborns.

Topics: Animals; Brain; Brain Edema; Butadienes; Cannabinoids; Cell Proliferation; Cells, Cultured; Disease Models, Animal; Extracellular Signal-Regulated MAP Kinases; Indoles; Intracranial Hemorrhages; Male; Microglia; Nerve Degeneration; Neuroimmunomodulation; Nitriles; Oxidative Stress; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Protein Kinase Inhibitors; Random Allocation; Receptor, Cannabinoid, CB2; Thrombin

Thrombin mediates the life-threatening cerebral edema and blood-brain barrier (BBB) damage that occurs after intracerebral hemorrhage (ICH). We previously found that the selective cannabinoid receptor 2 (CB2R) agonist JWH-133 reduced brain edema and neurological deficits following germinal matrix hemorrhage (GMH). We explored whether CB2R stimulation ameliorated thrombin-induced brain edema and BBB permeability as well as the possible molecular mechanism involved. A total of 144 Sprague-Dawley (S-D) rats received a thrombin (20 U) injection in the right basal ganglia. JWH-133 (1.5 mg/kg) or SR-144528 (3.0 mg/kg) and vehicle were intraperitoneally (i.p.) injected 1 h after surgery. Brain water content measurement, Evans blue (EB) extravasation, Western blot, and immunofluorescence were used to study the effects of a CB2R agonist 24 h after surgery. The results demonstrated that JWH-133 administration significantly decreased thrombin-induced brain edema and reduced the number of Iba-1-positive microglia. JWH-133 also decreased the number of P44/P42(+)/Iba-1(+) microglia, lowered Evans blue extravasation, and inhibited the elevated matrix metallopeptidase (MMP)-9 and matrix metallopeptidase (MMP)-12 activities. However, a selective CB2R antagonist (SR-144528) reversed these effects. We demonstrated that CB2R stimulation reduced thrombin-induced brain edema and alleviated BBB damage. We also found that matrix metalloproteinase suppression may be partially involved in these processes.

Topics: Animals; Blood-Brain Barrier; Brain Edema; Brain Injuries; Cannabinoids; Disease Models, Animal; Male; Matrix Metalloproteinases; Microglia; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Permeability; Phosphorylation; Rats; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB2; Thrombin; Zonula Occludens-1 Protein

The endocannabinoid CB2 receptor system has been implicated in the neuropathology of Alzheimer's disease (AD). In order to investigate the impact of the CB2 receptor system on AD pathology, a colony of mice with a deleted CB2 receptor gene, CNR2, was established on a transgenic human mutant APP background for pathological comparison with CB2 receptor-sufficient transgenic mice. J20 APP (PDGFB-APPSwInd) mice were bred over two generations with CNR2(-/-) (Cnr2(tm1Dgen)/J) mice to produce a colony of J20 CNR2(+/+) and J20 CNR2(-/-) mice. Seventeen J20 CNR2(+/+) mice (12 females, 5 males) and 16 J20 CNR2(-/-) mice (11 females, 5 males) were killed at 12 months, and their brains were interrogated for AD-related pathology with both biochemistry and immunocytochemistry (ICC). In addition to amyloid-dependent endpoints such as soluble Aβ production and plaque deposition quantified with 6E10 staining, the effect of CB2 receptor deletion on total soluble mouse tau production was assayed by using a recently developed high-sensitivity assay. Results revealed that soluble Aβ42 and plaque deposition were significantly increased in J20 CNR2(-/-) mice relative to CNR2(+/+) mice. Microgliosis, quantified with ionized calcium-binding adapter molecule 1 (Iba-1) staining, did not differ between groups, whereas plaque associated microglia was more abundant in J20 CNR2(-/-) mice. Total tau was significantly suppressed in J20 CNR2(-/-) mice relative to J20 CNR2(+/+) mice. The results confirm the constitutive role of the CB2 receptor system both in reducing amyloid plaque pathology in AD and also support tehpotential of cannabinoid therapies targeting CB2 to reduce Aβ; however, the results suggest that interventions may have a divergent effect on tau pathology.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Brain; Calcium-Binding Proteins; Cannabinoid Receptor Agonists; Cannabinoids; Disease Models, Animal; DNA-Binding Proteins; Female; Humans; Male; Mice, Transgenic; Microfilament Proteins; Microglia; Plaque, Amyloid; Polycomb-Group Proteins; Receptor, Cannabinoid, CB2; tau Proteins; Transcription Factors

Early brain injury (EBI) which comprises of vasogenic edema and apoptotic cell death is an important component of subarachnoid hemorrhage (SAH) pathophysiology. This study evaluated whether cannabinoid receptor type 2 (CB2R) agonist, JWH133, attenuates EBI after SAH and whether CB2R stimulation reduces pro-apoptotic caspase-3 via up-regulation of cAMP response element-binding protein (CREB)-Bcl-2 signaling pathway. Male Sprague-Dawley rats (n=123) were subjected to SAH by endovascular perforation. Rats received vehicle or JWH133 at 1h after SAH. Neurological deficits and brain water content were evaluated at 24h after SAH. Western blot was performed to quantify phosphorylated CREB (pCREB), Bcl-2, and cleaved caspase-3 levels. Neuronal cell death was evaluated with terminal deoxynucleotidyl transferase-mediated uridine 5'-triphosphate-biotin nick end-labeling staining. Additionally, CREB siRNA was administered to manipulate the proposed pathway. JWH133 (1.0mg/kg) improved neurological deficits and reduced brain water content in left hemisphere 24h after SAH. JWH133 significantly increased activated CREB (pCREB) and Bcl-2 levels and significantly decreased cleaved caspase-3 levels in left hemisphere 24h after SAH. CREB siRNA reversed the effects of treatment. TUNEL positive neurons in the cortex were reduced with JWH133 treatment. Thus, CB2R stimulation attenuated EBI after SAH possibly through activation of pCREB-Bcl-2 pathway.

Topics: Animals; Apoptosis; Brain Injuries; Cannabinoids; Caspase 3; CREB-Binding Protein; Disease Models, Animal; Enzyme Inhibitors; Male; Phosphorylation; Proto-Oncogene Proteins c-bcl-2; Rats; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB2; Signal Transduction; Subarachnoid Hemorrhage; Time Factors

Hypercholesterolemia is one of the most important risk factors for erectile dysfunction, mostly due to the impairment of oxidative stress and endothelial function in the penis. The cannabinoid system might regulate peripheral mechanisms of sexual function; however, its role is still poorly understood. We investigated the effects of CB2 activation on oxidative stress and fibrosis within the corpus cavernosum of hypercholesterolemic mice. Apolipoprotein-E-knockout mice were fed with a western-type diet for 11 weeks and treated with JWH-133 (selective CB2 agonist) or vehicle during the last 3 weeks. CB2 receptor expression, total collagen content, and reactive oxygen species (ROS) production within the penis were assessed. In vitro corpus cavernosum strips preparation was performed to evaluate the nitric oxide (NO) bioavailability. CB2 protein expression was shown in cavernosal endothelial and smooth muscle cells of wild type and hypercholesterolemic mice. Treatment with JWH-133 reduced ROS production and NADPH-oxidase expression in hypercholesterolemic mice penis. Furthermore, JWH-133 increased endothelial NO synthase expression in the corpus cavernosum and augmented NO bioavailability. The decrease in oxidative stress levels was accompanied with a reduction in corpus cavernosum collagen content. In summary, CB2 activation decreased histological features, which were associated with erectile dysfunction in hypercholesterolemic mice.

Topics: Animals; Cannabinoids; Disease Models, Animal; Erectile Dysfunction; Fibrosis; Hypercholesterolemia; Lipids; Male; Mice; Mice, Knockout; NADPH Oxidases; Nitric Oxide; Nitric Oxide Synthase Type III; Penis; Reactive Oxygen Species; Receptor, Cannabinoid, CB2

The endocannabinoid system has been shown to mediate beneficial effects on gastrointestinal inflammation via cannabinoid receptors 1 (CB(1)) and 2 (CB(2)). These receptors have also been reported to activate the MAP kinases p38 and c-Jun NH(2)-terminal kinase (JNK), which are involved in early acinar events leading to acute pancreatitis and induction of proinflammatory cytokines. Our aim was to examine the role of cannabinoid receptor activation in an experimental model of acute pancreatitis and the potential involvement of MAP kinases. Cerulein pancreatitis was induced in wild-type, CB(1)-/-, and MK2-/- mice pretreated with selective cannabinoid receptor agonists or antagonists. Severity of pancreatitis was determined by serum amylase and IL-6 levels, intracellular activation of pancreatic trypsinogen, lung myeloperoxidase activity, pancreatic edema, and histological examinations. Pancreatic lysates were investigated by Western blotting using phospho-specific antibodies against p38 and JNK. Quantitative PCR data, Western blotting experiments, and immunohistochemistry clearly show that CB(1) and CB(2) are expressed in mouse pancreatic acini. During acute pancreatitis, an upregulation especially of CB(2) on apoptotic cells occurred. The unselective CB(1)/CB(2) agonist HU210 ameliorated pancreatitis in wild-type and CB(1)-/- mice, indicating that this effect is mediated by CB(2). Furthermore, blockade of CB(2), not CB(1), with selective antagonists engraved pathology. Stimulation with a selective CB(2) agonist attenuated acute pancreatitis and an increased activation of p38 was observed in the acini. With use of MK2-/- mice, it could be demonstrated that this attenuation is dependent on MK2. Hence, using the MK2-/- mouse model we reveal a novel CB(2)-activated and MAP kinase-dependent pathway that modulates cytokine expression and reduces pancreatic injury and affiliated complications.

Topics: Amylases; Animals; Anti-Inflammatory Agents; Apoptosis; Blotting, Western; Cannabinoids; Ceruletide; Disease Models, Animal; Dronabinol; Edema; Enzyme Activation; Immunohistochemistry; Interleukin-6; Intracellular Signaling Peptides and Proteins; Lung; Mice; Mice, Inbred C57BL; Mice, Knockout; p38 Mitogen-Activated Protein Kinases; Pancreas, Exocrine; Pancreatitis; Peroxidase; Phosphorylation; Polymerase Chain Reaction; Protein Serine-Threonine Kinases; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Trypsinogen

Inflammatory bowel disease (IBD) is a chronic intestinal inflammation caused by hyperactivated effector immune cells that produce pro-inflammatory cytokines. Recent studies have shown that the cannabinoid system may play a critical role in mediating protection against intestinal inflammation. However, the effect of cannabinoid receptor induction after chronic colitis progression has not been investigated. Here, we investigate the effect of cannabinoid receptor-2 (CB2) agonist, JWH-133, after chronic colitis in IL-10(-/-) mice. JWH-133 effectively attenuated the overall clinical score, and reversed colitis-associated pathogenesis and decrease in body weight in IL-10(-/-) mice. After JWH-133 treatment, the percentage of CD4(+) T cells, neutrophils, mast cells, natural killer (NK1.1) cells, and activated T cells declined in the intestinal lamina propria (LP) and mesenteric lymph nodes (MLN) of mice with chronic colitis. JWH-133 was also effective in ameliorating dextran sodium sulfate (DSS)-induced colitis. In this model, JWH-133 reduced the number and percentage of macrophages and IFN-γ expressing cells that were induced during colitis progression. Treatment with aminoalkylindole 6-iodo-pravadoline (AM630), a CB2 receptor antagonist, reversed the colitis protection provided by JWH-133 treatment. Also, activated T cells were found to undergo apoptosis following JWH-133 treatment both in-vivo and in-vitro. These findings suggest that JWH-133 mediates its effect through CB2 receptors, and ameliorates chronic colitis by inducing apoptosis in activated T cells, reducing the numbers of activated T cells, and suppressing induction of mast cells, NK cells, and neutrophils at sites of inflammation in the LP. These results support the idea that the CB2 receptor agonists may serve as a therapeutic modality against IBD.

Topics: Animals; Apoptosis; Body Weight; Cannabinoids; Chronic Disease; Colitis; Dextran Sulfate; Disease Models, Animal; Disease Progression; Female; Interleukin-10; Killer Cells, Natural; Mast Cells; Mice; Mice, Inbred C57BL; Mice, Knockout; Neutrophils; Receptor, Cannabinoid, CB2; T-Lymphocytes

Alzheimer's disease (AD) brain shows an ongoing inflammatory condition and non-steroidal anti-inflammatories diminish the risk of suffering the neurologic disease. Cannabinoids are neuroprotective and anti-inflammatory agents with therapeutic potential.. We have studied the effects of prolonged oral administration of transgenic amyloid precursor protein (APP) mice with two pharmacologically different cannabinoids (WIN 55,212-2 and JWH-133, 0.2 mg/kg/day in the drinking water during 4 months) on inflammatory and cognitive parameters, and on ¹⁸F-fluoro-deoxyglucose (¹⁸FDG) uptake by positron emission tomography (PET).. Novel object recognition was significantly reduced in 11 month old Tg APP mice and 4 month administration of JWH was able to normalize this cognitive deficit, although WIN was ineffective. Wild type mice cognitive performance was unaltered by cannabinoid administration. Tg APP mice showed decreased ¹⁸FDG uptake in hippocampus and cortical regions, which was counteracted by oral JWH treatment. Hippocampal GFAP immunoreactivity and cortical protein expression was unaffected by genotype or treatment. In contrast, the density of Iba1 positive microglia was increased in Tg APP mice, and normalized following JWH chronic treatment. Both cannabinoids were effective at reducing the enhancement of COX-2 protein levels and TNF-α mRNA expression found in the AD model. Increased cortical β-amyloid (Aβ) levels were significantly reduced in the mouse model by both cannabinoids. Noteworthy both cannabinoids enhanced Aβ transport across choroid plexus cells in vitro.. In summary we have shown that chronically administered cannabinoid showed marked beneficial effects concomitant with inflammation reduction and increased Aβ clearance.

Topics: Administration, Oral; Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Analysis of Variance; Animals; Benzoxazines; Cannabinoids; Choroid Plexus; Cognition Disorders; Corpus Striatum; Cyclooxygenase 2; Disease Models, Animal; Encephalitis; Enzyme-Linked Immunosorbent Assay; Fluorodeoxyglucose F18; Gene Expression Regulation; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Humans; Mice; Mice, Transgenic; Microglia; Morpholines; Naphthalenes; Positron-Emission Tomography; Receptor, Cannabinoid, CB2; RNA, Messenger; Time Factors

Previous studies have shown that modulation of the receptor-mediated cannabinoid system during neuroinflammation can produce potent neuroprotective and anti-inflammatory effects. However, in this context, little is known about how selective activation of the cannabinoid type-2 receptor (CB2R) affects the activated state of the brain endothelium and blood-brain barrier (BBB) function. Using human brain tissues and primary human brain microvascular endothelial cells (BMVECs), we demonstrate that the CB2R is highly upregulated during inflammatory insult. We then examined whether the CB2R agonists could attenuate inflammatory responses at the BBB using a mouse model of LPS-induced encephalitis and highly selective CB2R agonists. Visualization by intravital microscopy revealed that administration of JWH133 [(6aR,10aR)-3-(1,1-dimethylbutyl)-6a,7,10,10a-tetrahydro-6,6,9-trimethyl-6H-dibenzo[b,d]pyran] or a novel resorcinol-based compound, O-1966 (1-[4-(1,1-dimethyl-heptyl)-2,6-dimethoxy-phenyl]-3-methyl-cyclohexanol), greatly attenuated leukocyte adhesion in surface pial vessels and in deep ascending cortical postcapillary venules. BBB permeability assessments with small and large fluorescent tracers showed that CB2R agonists were effective at preventing barrier leakiness after LPS administration. To determine whether the effects by CB2R agonists on barrier protection are not only due to the CB2R modulation of immune cell function, we tested the agonists in vitro with barrier-forming primary BMVECs. Remarkably, the addition of CB2R agonist increased transendothelial electrical resistance and increased the amount of tight junction protein present in membrane fractions. Furthermore, CB2R agonists decreased the induction of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 surface expression in BMVECs exposed to various proinflammatory mediators. Together, these results suggest that pharmacological CB2R ligands offer a new strategy for BBB protection during neuroinflammation.

Topics: Animals; Anisoles; Blood-Brain Barrier; Camphanes; Cannabinoids; Capillary Permeability; Cell Adhesion; Cells, Cultured; Cyclohexanols; Dextrans; Disease Models, Animal; Electric Impedance; Encephalitis; Endothelial Cells; Endothelium; Flow Cytometry; Fluorescein-5-isothiocyanate; Gene Expression Regulation; Humans; Intercellular Adhesion Molecule-1; Leukocytes; Lipopolysaccharides; Membrane Proteins; Mice; Mice, Inbred C57BL; Mice, Knockout; Phosphoproteins; Platelet Endothelial Cell Adhesion Molecule-1; Pyrazoles; Receptor, Cannabinoid, CB2; Statistics, Nonparametric; Tumor Necrosis Factor-alpha; Vascular Cell Adhesion Molecule-1; Zonula Occludens-1 Protein

Topics: Animals; Brain; Cannabinoids; Disease Models, Animal; Humans; Mice; Mice, Knockout; Models, Biological; Parvalbumins; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Substance-Related Disorders

The endocannabinoid system is crucially involved in the regulation of brain activity and inflammation. We have investigated the localization of cannabinoid CB1 and CB2 receptors in adult rat brains before and after focal cerebral ischemia due to endothelin-induced transient occlusion of the middle cerebral artery (eMCAO). Using immunohistochemistry, both receptor subtypes were identified in cortical neurons. After eMCAO, neuronal cell death was accompanied by reduced neuronal CB1 and CB2 receptor-linked immunofluorescence. In parallel, CB1 receptor was found in activated microglia/macrophages 3 days post eMCAO and in astroglia cells at days 3 and 7. CB2 receptor labeling was identified in activated microglia/macrophages or astroglia 3 and 7d ays post ischemia, respectively. In addition, immune competent CD45-positive cells were characterized by pronounced CB2 receptor staining 3 and 7 days post eMCAO. KN38-72717, a potent and selective CB1 and CB2 receptor agonist, revealed a significant, dose-dependent and long-lasting reduction of cortical lesion sizes due to eMCAO, when applied consecutively before, during and after eMCAO. In addition, severe motor deficits of animals suffering from eMCAO were significantly improved by KN38-7271. KN38-7271 remained effective, even if its application was delayed up to 6h post eMCAO. Finally, we show that the endocannabinoid system assembles a comprehensive machinery to defend the brain against the devastating consequences of cerebral ischemia. In summary, this study underlines the therapeutic potential of CB1 and/or CB2 receptor agonists against neurodegenerative diseases or injuries involving acute or chronic imbalances of cerebral blood flow and energy consumption.

Topics: Animals; Arachidonic Acids; Brain; Brain Infarction; Cannabinoids; Disease Models, Animal; Dose-Response Relationship, Drug; Ectodysplasins; Endocannabinoids; Gene Expression Regulation; Glial Fibrillary Acidic Protein; Indans; Infarction, Middle Cerebral Artery; Leukocyte Common Antigens; Male; Movement Disorders; Neuroprotective Agents; Polyunsaturated Alkamides; Psychomotor Performance; Quinoxalines; Rats; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Sulfonic Acids; Time Factors

Strong evidence supports a protective role of the cannabinoid receptor 2 (CB(2)) in inflammation and atherosclerosis. However, direct proof of its involvement in lesion formation is lacking. Therefore, the present study aimed to characterize the role of the CB(2) receptor in Murine atherogenesis.. Low density lipoprotein receptor-deficient (LDLR(-/-)) mice subjected to intraperitoneal injections of the selective CB(2) receptor agonist JWH-133 or vehicle three times per week consumed high cholesterol diet (HCD) for 16 weeks. Surprisingly, intimal lesion size did not differ between both groups in sections of the aortic roots and arches, suggesting that CB(2) activation does not modulate atherogenesis in vivo. Plaque content of lipids, macrophages, smooth muscle cells, T cells, and collagen were also similar between both groups. Moreover, CB(2) (-/-)/LDLR(-/-) mice developed lesions of similar size containing more macrophages and lipids but similar amounts of smooth muscle cells and collagen fibers compared with CB(2) (+/+)/LDLR(-/-) controls. While JWH-133 treatment reduced intraperitoneal macrophage accumulation in thioglycollate-elicited peritonitis, neither genetic deficiency nor pharmacologic activation of the CB(2) receptor altered inflammatory cytokine expression in vivo or inflammatory cell adhesion in the flow chamber in vitro.. Our study demonstrates that both activation and deletion of the CB(2) receptor do not relevantly modulate atherogenesis in mice. Our data do not challenge the multiple reports involving CB(2) in other inflammatory processes. However, in the context of atherosclerosis, CB(2) does not appear to be a suitable therapeutic target for reduction of the atherosclerotic plaque.

Topics: Animals; Atherosclerosis; Cannabinoids; Cell Survival; Cytokines; Disease Models, Animal; Endothelial Cells; Feeding Behavior; Inflammation; Intercellular Adhesion Molecule-1; Mass Spectrometry; Mice; Mice, Inbred C57BL; Monocytes; Receptor, Cannabinoid, CB2; Signal Transduction

The cannabinoid receptor 2 (CB2) plays a pleiotropic role in innate immunity and is a crucial mediator of liver disease. In this study, we investigated the impact of CB2 receptors on the regenerative process associated with liver injury. Following acute hepatitis induced by carbon tetrachloride (CCl(4)), CB2 was induced in the nonparenchymal cell fraction and remained undetectable in hepatocytes. Administration of CCl(4) to CB2(-/-) mice accelerated liver injury, as shown by increased alanine/aspartate aminotransferase levels and hepatocyte apoptosis, and delayed liver regeneration, as reflected by a retarded induction of hepatocyte proliferating cell nuclear antigen expression; proliferating cell nuclear antigen induction was also delayed in CB2(-/-) mice undergoing partial hepatectomy. Conversely, following treatment with the CB2 agonist JWH-133, CCl(4)-treated WT mice displayed reduced liver injury and accelerated liver regeneration. The CCl(4)-treated CB2(-/-) mice showed a decrease in inducible nitric oxide synthase and tumor necrosis factor-alpha expression, and administration of the nitric oxide donor moldomine (SIN-1) to these animals reduced hepatocyte apoptosis, without affecting liver regeneration. Impaired liver regeneration was consecutive to an interleukin-6 (IL-6)-mediated decrease in matrix metalloproteinase 2 (MMP-2) activity. Indeed, CCl(4)-treated CB2(-/-) mice displayed lower levels of hepatic IL-6 messenger RNA and increased MMP-2 activity. Administration of IL-6 to these mice decreased MMP-2 activity and improved liver regeneration, without affecting hepatocyte apoptosis. Accordingly, administration of the MMP inhibitor CTTHWGFTLC to CCl(4)-treated CB2(-/-) mice improved liver regeneration. Finally, in vitro studies demonstrated that incubation of hepatic myofibroblasts with JWH-133 increased tumor necrosis factor-alpha and IL-6 and decreased MMP-2 expressions.. CB2 receptors reduce liver injury and promote liver regeneration following acute insult, via distinct paracrine mechanisms involving hepatic myofibroblasts. These results suggest that CB2 agonists display potent hepatoprotective properties, in addition to their antifibrogenic effects.

Topics: Alanine Transaminase; Animals; Apoptosis; Aspartate Aminotransferases; Cannabinoids; Carbon Tetrachloride; Cells, Cultured; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Hepatectomy; Hepatocytes; Interleukin-6; Liver Regeneration; Matrix Metalloproteinase 2; Mice; Mice, Inbred C57BL; Mice, Knockout; Paracrine Communication; Proliferating Cell Nuclear Antigen; Receptor, Cannabinoid, CB2; Tumor Necrosis Factor-alpha

Preventive treatment with cannabinoid agonists has been reported to reduce the infarct size in a mouse model of myocardial ischemia/reperfusion. Here we investigated the possible cardioprotective effect of selective CB(2) cannabinoid receptor activation during ischemia. We performed left coronary artery ligature in C57Bl/6 mice for 30 min, followed by 24 h of reperfusion. Five minutes before reperfusion, mice received intraperitoneal injection of the CB(2) selective agonist JWH-133 (20 mg/kg) or vehicle. Infarct size was assessed histologically and by cardiac troponin I (cTnI) ELISA. Immunohistochemical analysis of leukocyte infiltration, oxidative stress in situ quantification, real-time RT-PCR analysis of inflammatory mediators as well as western blots for kinase phosphorylation was also performed. In addition, we studied chemotaxis and integrin expression of human neutrophils in vitro. JWH-133 significantly reduced the infarct size (I/area at risk: 19.27%+/-1.91) as compared to vehicle-treated mice (31.77%+/-2.7). This was associated with a reduction of oxidative stress and neutrophil infiltration in the infarcted myocardium, whereas activation of ERK 1/2 and STAT-3 was increased. Preinjection of PI3K inhibitor LY294002, MEK 1/2 inhibitor U0126 and JAK-2 inhibitor AG-490 partially abrogated the JWH-133 mediated infarct size reduction. No changes in cardiac CXCL1, CXCL2, CCL3, TNF-alpha, and ICAM-1 expression levels were found. Furthermore, JWH-133 inhibited the TNF-alpha induced chemotaxis and integrin CD18/CD11b (Mac-1) upregulation on human neutrophils. Our data suggest that JWH-133 administration during ischemia reduces the infarct size in a mouse model of myocardial ischemia/reperfusion through a direct cardioprotective activity on cardiomyocytes and neutrophils.

Topics: Animals; Cannabinoids; CD11b Antigen; Cell Movement; Chemotactic Factors; Disease Models, Animal; Humans; Intercellular Adhesion Molecule-1; Intracellular Space; Mice; Myocardial Infarction; Myocardial Reperfusion Injury; Myocardium; Neutrophils; Oxidative Stress; Reactive Oxygen Species; Receptor, Cannabinoid, CB2; Signal Transduction; Tumor Necrosis Factor-alpha

Activation of cannabinoid (CB)(1) receptors results in attenuation of experimental colitis. Our aim was to examine the role of CB(2) receptors in experimental colitis using agonists (JWH133, AM1241) and an antagonist (AM630) in trinitrobenzene sulfonic acid (TNBS)-induced colitis in wildtype and CB(2) receptor-deficient (CB(2) (-/-)) mice.. Mice were treated with TNBS to induce colitis and then given intraperitoneal injections of the CB(2) receptor agonists JWH133, AM1241, or the CB(2) receptor antagonist AM630. Additionally, CB(2) (-/-) mice were treated with TNBS and injected with JWH133 or AM1241. Animals were examined 3 days after the induction of colitis. The colons were removed for macroscopic and microscopic evaluation, as well as the determination of myeloperoxidase activity. Quantitative reverse-transcriptase polymerase chain reaction (RT-PCR) for CB(2) receptor was also performed in animals with TNBS and dextran sodium sulfate colitis.. Intracolonic installation of TNBS caused severe colitis. CB(2) mRNA expression was significantly increased during the course of experimental colitis. Three-day treatment with JWH133 or AM1241 significantly reduced colitis; AM630 exacerbated colitis. The effect of JWH133 was abolished when animals were pretreated with AM630. Neither JWH133 nor AM1241 had effects in CB(2) (-/-) mice.. We show that activation of the CB(2) receptor protects against experimental colitis in mice. Increased expression of CB(2) receptor mRNA and aggravation of colitis by AM630 suggests a role for this receptor in normally limiting the development of colitis. These results support the idea that the CB(2) receptor may be a possible novel therapeutic target in inflammatory bowel disease.

Topics: Animals; Cannabinoids; Colitis; Disease Models, Animal; Female; Gene Expression; Indoles; Inflammatory Bowel Diseases; Male; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Receptor, Cannabinoid, CB2

Cannabinoids have been shown to inhibit sensory nerve activation in guinea-pigs and humans. Their effects are mediated by specific activation of two types of receptors, named CB(1) and CB(2). The purpose of this study was to investigate the effects of WIN 55,212-2, (R)-(+)-[2,3-dihydro-5methyl-3-[(4-morpholino)methyl]pyrrolo-[1,2,3-de]-1,4-benzoxazin-6-yl](1-naphthyl)methanone, a non selective agonist of cannabinoid receptors, and JWH 133, (6aR,10aR)-3-(1,1-dimethylbutyl)-6a,7,10,10a-tetrahydro-6,6,9-trimethyl-6H-dibenzo[b,d]pyran a selective cannabinoid CB(2) receptor agonist, on the sensory nerve component of intraoesophageal (i.oe.) HCl-induced airway microvascular leakage and bronchoconstriction in guinea-pigs. We also tested the effect of WIN 55,212-2 on substance P-induced plasma extravasation and bronchoconstriction. Airway microvascular leakage and bronchoconstriction induced by i.oe. HCl was inhibited by the cannabinoid CB(1)/CB(2) agonist WIN 55,212-2 (0.3-3 mg/kg i.p.) in a dose-dependent manner (maximal inhibition at the dose of 3 mg kg(-1), P<0.01). The effect of WIN 55,212-2 was inhibited by a cannabinoid CB(2) receptor antagonist SR 144528, [N-[(1S)-endo-1,3,3-trimethylbicyclo[2,2,1] heptan-2yl]-5-(-4-chloro-3-methylphenyl)-1-(4-methylbenzyl)pyrazole-3-carboxamide], but not by a CB(1) receptor antagonist, SR 141716, [N-(piperidin-1yl)-5-(-4-chlorophenyl)-1-(2,4dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide hydrochloride]. The cannabinoid CB(2) agonist JWH 133 (0.3-3 mg/kg i.p.) mimicked the inhibitory effect of WIN 55,212-2 on HCl-induced microvascular leakage. Under similar conditions, WIN 55,212-2 (1 mg kg (-1) i.p.) was unable to counteract the airway microvascular leakage and bronchoconstriction induced by substance P. These results suggest that inhibition by WIN 55,212-2 of airway plasma extravasation and bronchoconstriction induced by i.oe. HCl instillation in guinea-pigs is mediated through cannabinoid CB(2) receptor activation.

Topics: Airway Obstruction; Animals; Benzoxazines; Bronchi; Bronchoconstriction; Camphanes; Cannabinoids; Capillary Permeability; Disease Models, Animal; Dose-Response Relationship, Drug; Esophagus; Extravasation of Diagnostic and Therapeutic Materials; Gastroesophageal Reflux; Guinea Pigs; Hydrochloric Acid; Male; Morpholines; Naphthalenes; Piperidines; Pulmonary Edema; Pyrazoles; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Respiratory Function Tests; Rimonabant; Trachea

Targeting cannabinoid-2 (CB(2)) receptors with selective agonists may represent a novel therapeutic avenue in various inflammatory diseases, but the mechanisms by which CB(2) activation exerts its anti-inflammatory effects and the cellular targets are elusive. Here, we investigated the effects of CB(2)-receptor activation on TNF-alpha-induced signal transduction in human coronary artery endothelial cells in vitro and on endotoxin-induced vascular inflammatory response in vivo. TNF-alpha induced NF-kappaB and RhoA activation and upregulation of adhesion molecules ICAM-1 and VCAM-1, increased expression of monocyte chemoattractant protein, enhanced transendothelial migration of monocytes, and augmented monocyte-endothelial adhesion. Remarkably, all of the above-mentioned effects of TNF-alpha were attenuated by CB(2) agonists. CB(2) agonists also decreased the TNF-alpha- and/or endotoxin-induced ICAM-1 and VCAM-1 expression in isolated aortas and the adhesion of monocytes to aortic vascular endothelium. CB(1) and CB(2) receptors were detectable in human coronary artery endothelial cells by Western blotting, RT-PCR, real-time PCR, and immunofluorescence staining. Because the above-mentioned TNF-alpha-induced phenotypic changes are critical in the initiation and progression of atherosclerosis and restenosis, our findings suggest that targeting CB(2) receptors on endothelial cells may offer a novel approach in the treatment of these pathologies.

Topics: Animals; Anti-Inflammatory Agents; Aorta; Cannabinoids; Cells, Cultured; Chemokine CCL2; Coronary Vessels; Disease Models, Animal; Dose-Response Relationship, Drug; Endothelial Cells; Humans; Inflammation; Intercellular Adhesion Molecule-1; Leukocyte Rolling; Lipopolysaccharides; Male; Mice; Mice, Inbred C57BL; Monocytes; NF-kappa B; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; rhoA GTP-Binding Protein; RNA, Messenger; Signal Transduction; Tumor Necrosis Factor-alpha; Vascular Cell Adhesion Molecule-1

Oil of mustard (OM) is a potent neuronal activator that is known to elicit visceral hyperalgesia when given intracolonically, but the full extent to which OM is also proinflammatory in the gastrointestinal tract is not known. We have previously shown that male CD-1 mice given a single administration of 0.5% OM develop a severe colitis that is maximum at day 3 and that gradually lessens until essentially absent by day 14. OM-induced neuronal stimulation is reported to be reduced by cannabinoid agonists, and cannabinoid receptor 1 (CB1R)-/- mice have exacerbated experimental colitis. Therefore, we examined the role of cannabinoids in this OM-induced 3-day model of colitis in CD-1 mice and in a 7-day dextran sulfate sodium (DSS) colitis model in BALB/c mice. In OM colitis, the CB1R-selective agonist ACEA and the CB2R-selective agonist JWH-133 reduced (P < 0.05) colon weight gain (means +/- SE; 82 +/- 13% and 47 +/- 15% inhibition, respectively), colon shrinkage (98 +/- 24% and 42 +/- 12%, respectively), colon inflammatory damage score (49 +/- 11% and 40 +/- 12%, respectively), and diarrhea (58 +/- 12% and 43 +/- 11%, respectively). Histological damage was similarly reduced by these treatments. Likewise, CBR agonists attenuated DSS colitis, albeit at higher doses; ACEA at 10 mg/kg, twice daily, inhibited (P < 0.05) macroscopic and microscopic scores (46 +/- 9% and 63 +/- 7%, respectively); whereas 20 mg/kg, twice daily, of JWH-133 was required to diminish (P < 0.05) macroscopic and microscopic scores (29 +/- 7% and 43 +/- 5%, respectively). CB1R and CB2R immunostaining of colon sections revealed that CB1R in enteric neurons was more intense in colitic vs. control mice; however, CB1R was also increased in the endothelial layer in OM colitis only. CB2R immunostaining was more marked in infiltrated immune cells in OM colitis. These findings validate the OM colitis model with respect to the DSS model and provide strong support to the emerging idea that cannabinoid receptor activation mediates protective mechanisms in experimental colitis. The demonstration of CB1R agonist effects in colitis support the neurogenic nature of the OM-induced colitis model and reinforce the importance of neuronal activation in intestinal inflammation.

Topics: Animals; Arachidonic Acids; Cannabinoids; Colitis; Dextran Sulfate; Disease Models, Animal; Male; Mice; Mice, Inbred BALB C; Mustard Plant; Plant Oils; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Treatment Outcome

Peripheral cannabinoid 2 receptors (CB2 receptors) modulate immune responses and attenuate nociceptive behaviour in models of acute and persistent pain. The aim of the present study was to investigate whether peripheral CB2 receptors modulate spinal processing of innocuous and noxious responses and to determine whether there are altered roles of CB2 receptors in models of persistent pain. Effects of local administration of the CB2 receptor agonist JWH-133 (5 and 15 microg/50 microL) on mechanically evoked responses of spinal wide dynamic range (WDR) neurons in noninflamed rats, rats with carrageenan-induced hindpaw inflammation, sham operated rats and spinal nerve-ligated (SNL) rats were determined in anaesthetized rats in vivo. Mechanical stimulation (von Frey filaments, 6-80 g) of the peripheral receptive field evoked firing of WDR neurons. Mechanically evoked responses of WDR neurons were similar in noninflamed, carrageenan-inflamed, sham-operated and SNL rats. Intraplantar injection of JWH-133 (15 microg), but not vehicle, significantly (P < 0.05) inhibited innocuous and noxious mechanically evoked responses of WDR neurons in all four groups of rats. In many cases the selective CB2 receptor antagonist, SR144528 (10 microg/50 microL), attenuated the inhibitory effects of JWH-133 (15 microg) on mechanically evoked WDR neuronal responses. The CB1 receptor antagonist, SR141716A, did not attenuate the inhibitory effects of JWH-133 on these responses. Intraplantar preadministration of JWH-133 also inhibited (P < 0.05) carrageenan-induced expansion of peripheral receptive fields of WDR dorsal horn neurons. This study demonstrates that activation of peripheral CB2 receptors attenuates both innocuous- and noxious-evoked responses of WDR neurons in models of acute, inflammatory and neuropathic pain.

Topics: Action Potentials; Animals; Camphanes; Cannabinoids; Carrageenan; Disease Models, Animal; Inflammation; Ligation; Male; Neural Inhibition; Neuralgia; Nociceptors; Peripheral Nervous System Diseases; Physical Stimulation; Piperidines; Posterior Horn Cells; Pyrazoles; Rats; Rats, Sprague-Dawley; Reaction Time; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Rimonabant; Sensory Receptor Cells; Spinal Nerves