piperidines and arachidonoylserotonin

The cannabinoid receptor 1 (CB1) and transient receptor potential cation channel subfamily V member 1 (TRPV1) are proposed to mediate opposite behavioural responses. Their common denominator is the endocannabinoid ligand anandamide (AEA), which is believed to mediate antidepressant-like effect via CB1-R stimulation and depressive-like effect via TRPV1 activation. This is supposed to explain the bell-shaped dose-response curve for anandamide in preclinical models.. We investigated this assumption by administering the dual inhibitor of AEA hydrolysis and TRPV1 activation N-arachidonoyl-serotonin (AA-5HT) into the medial prefrontal cortex of rats. AA-5HT was given in three different doses (0.125, 0.250, 0.500 nmol/0.4 µl/side) and rat behaviour was assessed in the forced swim test.. Our results show significant antidepressant-like effect of AA-5HT (0.250 nmol) but no effects of low or high doses. The effect of 0.250 nmol AA-5HT was partially attenuated when coadministering the inverse CB1-agonist rimonabant (1.6 µg).. A 0.250 nmol of AA-5HT administration into the medial prefrontal cortex induced a significant antidepressant-like effect that was partially attenuated by locally blocking CB1-receptor.

Topics: Amidohydrolases; Animals; Antidepressive Agents; Arachidonic Acids; Behavior, Animal; Cannabinoid Receptor Antagonists; Depression; Dose-Response Relationship, Drug; Drug Inverse Agonism; Male; Piperidines; Prefrontal Cortex; Pyrazoles; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB1; Rimonabant; Serotonin; TRPV Cation Channels

Selective blockade of anandamide hydrolysis, through the inhibition of the FAAH enzyme, has anticonvulsant effects, which are mediated by CB1 receptors. Anandamide, however, also activates TRPV1 channels, generally with an opposite outcome on neuronal modulation. Thus, we suggested that the dual FAAH and TRPV1 blockade with N-arachidonoyl-serotonin (AA-5-HT) would be efficacious in inhibiting pentylenetetrazole (PTZ)-induced seizures in mice. We also investigated the contribution of CB1 activation and TRPV1 blockade to the overt effect of AA-5-HT. In the first experiment, injection of AA-5-HT (0.3-3.0 mg/kg) delayed the onset and reduced the duration of PTZ (60 mg)-induced seizures in mice. These effects were reversed by pre-treatment with the CB1 antagonist, AM251 (1.0-3.0 mg/kg). Finally, we observed that administration of the selective TRPV1 antagonist, SB366791 (0.1-1 mg/kg), did not entirely mimic AA-5-HT effects. In conclusion, AA-5-HT alleviates seizures in mice, an effect inhibited by CB1 antagonism, but not completely mimicked by TRPV1 blockage, indicating that the overall effect of AA-5-HT seems to depend mainly on CB1 receptors. This may represent a new strategy for the development of drugs against seizures, epilepsies and related syndromes.

Topics: Amidohydrolases; Anilides; Animals; Anticonvulsants; Arachidonic Acids; Cinnamates; Male; Mice; Pentylenetetrazole; Piperidines; Pyrazoles; Receptor, Cannabinoid, CB1; Seizures; Serotonin; TRPV Cation Channels

Neuropathic pain is a chronic disease resulting from dysfunction within the "pain matrix". The basolateral amygdala (BLA) can modulate cortical functions and interactions between this structure and the medial prefrontal cortex (mPFC) are important for integrating emotionally salient information. In this study, we have investigated the involvement of the transient receptor potential vanilloid type 1 (TRPV1) and the catabolic enzyme fatty acid amide hydrolase (FAAH) in the morphofunctional changes occurring in the pre-limbic/infra-limbic (PL/IL) cortex in neuropathic rats.. The effect of N-arachidonoyl-serotonin (AA-5-HT), a hybrid FAAH inhibitor and TPRV1 channel antagonist, was tested on nociceptive behaviour associated with neuropathic pain as well as on some phenotypic changes occurring on PL/IL cortex pyramidal neurons. Those neurons were identified as belonging to the BLA-mPFC pathway by electrical stimulation of the BLA followed by hind-paw pressoceptive stimulus application. Changes in their spontaneous and evoked activity were studied in sham or spared nerve injury (SNI) rats before or after repeated treatment with AA-5-HT. Consistently with the SNI-induced changes in PL/IL cortex neurons which underwent profound phenotypic reorganization, suggesting a profound imbalance between excitatory and inhibitory responses in the mPFC neurons, we found an increase in extracellular glutamate levels, as well as the up-regulation of FAAH and TRPV1 in the PL/IL cortex of SNI rats. Daily treatment with AA-5-HT restored cortical neuronal activity, normalizing the electrophysiological changes associated with the peripheral injury of the sciatic nerve. Finally, a single acute intra-PL/IL cortex microinjection of AA-5-HT transiently decreased allodynia more effectively than URB597 or I-RTX, a selective FAAH inhibitor or a TRPV1 blocker, respectively.. These data suggest a possible involvement of endovanilloids in the cortical plastic changes associated with peripheral nerve injury and indicate that therapies able to normalize endovanilloid transmission may prove useful in ameliorating the symptoms and central sequelae associated with neuropathic pain.

Topics: Amidohydrolases; Amygdala; Animals; Arachidonic Acids; Benzamides; Carbamates; Electric Stimulation; Electrodes; Electrophysiological Phenomena; Male; Microdialysis; Microinjections; Mononeuropathies; Neurons; Nociceptors; Piperidines; Prefrontal Cortex; Pyrazoles; Rats; Rats, Wistar; RNA, Messenger; Serotonin; TRPV Cation Channels

The endocannabinoid-inactivating enzyme, fatty acid amide hydrolase (FAAH), and the transient receptor potential vanilloid type-1 (TRPV1) channel are new targets for the development of anxiolytic drugs. We studied the effect on anxiety-like behavior in the elevated plus maze of a dual FAAH/TRPV1 blocker, N-arachidonoyl-serotonin (AA-5-HT). In male C57BL/6J mice, acute intraperitoneal administration of AA-5-HT (0.1-2.5 mg/kg) increased both the time spent and the number of entries in the open arm, while being inactive at the highest dose tested (5 mg/kg). AA-5-HT was more potent than selective blockers of FAAH or TRPV1 (URB597 and SB366791, respectively). In male Swiss mice, AA-5-HT had to be administered chronically to observe an anxiolytic effect at an intermediate dose (2.5 mg/kg), the highest dose (5 mg/kg) being anxiogenic, and 1 mg/kg being ineffective. In both strains, the anxiolytic effects of AA-5-HT were paralleled by elevation of brain endocannabinoid levels and were reversed by per se inactive doses of the cannabinoid receptors of type-1 (CB(1)) receptor antagonist AM251, or the TRPV1 agonist, olvanil. Immunohistochemical localization of CB(1) and TRPV1 receptors was observed in mouse prefrontal cortex, nucleus accumbens, amygdala, and hippocampus. Simultaneous 'indirect' activation of CB(1) receptors following FAAH inhibition, and antagonism at TRPV1 receptors might represent a new therapeutic strategy against anxiety.

Topics: Amidohydrolases; Anilides; Animals; Anti-Anxiety Agents; Anxiety; Arachidonic Acids; Benzamides; Brain; Cannabinoid Receptor Modulators; Capsaicin; Carbamates; Cinnamates; Diazepam; Exploratory Behavior; Male; Mice; Mice, Inbred C57BL; Piperidines; Pyrazoles; Receptor, Cannabinoid, CB1; Serotonin; TRPV Cation Channels

Dopamine and the endocannabinoids, anandamide and 2-arachidonoylglycerol, interact at several levels in the brain, with the involvement of both cannabinoid CB(1) receptors and transient receptor potential vanilloid type-1 (TRPV1) channels (which are alternative anandamide receptors). Using pharmacological, immunohistochemical and analytical approaches, we investigated the response of dopamine D(3) receptor null (D3R((-/-))) mice in models of epilepsy and anxiety, in relation to their brain endocannabinoid and endovanilloid tone. Compared to wild-type mice, D3R((-/-)) mice exhibited a delayed onset of clonic seizures, enhanced survival time, reduced mortality rate and more sensitivity to anticonvulsant effects of diazepam after intraperitoneal administration of picrotoxin (7 mg/kg), and a less anxious-like behaviour in the elevated plus maze test. D3R((-/-)) mice also exhibited different endocannabinoid and TRPV1, but not CB(1), levels in the hippocampus, nucleus accumbens, amygdala and striatum. Given the role played by CB(1) and TRPV1 in neuroprotection and anxiety, and based on data obtained here with pharmacological tools, we suggest that the alterations of endocannabinoid and endovanilloid tone found in D3R((-/-)) mice might account for part of their altered responses to excitotoxic and anxiogenic stimuli.

Topics: Analysis of Variance; Animals; Anti-Anxiety Agents; Anti-Inflammatory Agents, Non-Steroidal; Anxiety; Arachidonic Acids; Brain; Cannabinoid Receptor Modulators; Capsaicin; Diazepam; Disease Models, Animal; Dose-Response Relationship, Drug; Endocannabinoids; Epilepsy; GABA Antagonists; Male; Maze Learning; Mice; Mice, Inbred C57BL; Mice, Knockout; Picrotoxin; Piperidines; Pyrazoles; Reaction Time; Receptor, Cannabinoid, CB1; Receptors, Dopamine D3; Serotonin; TRPV Cation Channels

These studies investigated feeding responses to indirect activation of parabrachial cannabinoid CB1 receptors. Arachidonoyl serotonin (AA5HT), an inhibitor of the endocannabinoid degradative enzyme, fatty acid amide hydrolase (FAAH), was infused into the parabrachial nucleus of male Sprague-Dawley rats, and intakes of high-fat/sucrose pellets and standard rodent chow were subsequently evaluated under various feeding schedules. FAAH blockade stimulated the intake of high-fat/sucrose pellets that were presented daily for 4 h during the light period, with compensatory decreases in the consumption of standard chow during the ensuing 20 h. These diet-selective changes were repeated on the next day, indicating a shift in feeding toward the more palatable diet that lasted for 48 h after a single infusion. The cannabinoid CB1 receptor antagonist, AM251, blocked the orexigenic actions of AA5HT, implicating CB1 receptors in mediating the feeding responses to FAAH inactivation. When the feeding schedule was reversed, AA5HT produced nominal increases in the consumption of standard chow for the 4-h access period, but substantial increases in the intake of high-fat/sucrose during the following 20-h interval. When presented with only high-fat/sucrose diet for 24 h, AA5HT increased 24-h food intake. In contrast, when given 24-h access only to standard chow, AA5HT failed to affect intake. Therefore, indirectly activating parabrachial CB1 receptors by blocking the degradation of native ligands selectively stimulates the intake of palatable food, with differential actions on total energy intake depending upon the feeding schedule. Our results support a role for parabrachial cannabinoid mechanisms in providing physiological regulation to neural substrates modulating feeding, energy balance, and behavioral responses for natural reward.

Topics: Amidohydrolases; Animals; Arachidonic Acids; Brachial Plexus; Eating; Enzyme Inhibitors; Fluorescent Antibody Technique; Food Preferences; Immunohistochemistry; Male; Piperidines; Pyrazoles; Rats; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB1; Reward; Serotonin; Stimulation, Chemical

Evidence indicates that the endocannabinoid, 2-arachidonoylglycerol (2-AG), increases food intake when injected into the nucleus accumbens shell (NAcS), thereby potentially activating hypothalamic nuclei involved in food intake regulation. We aimed to evaluate potential orexigenic effects of the endocannabinoid anandamide and of AA5HT, a fatty acid amide hydrolase (FAAH) inhibitor, and OMDM-1, an inhibitor of anandamide uptake, injected in the NAcS, as well as the effect of these treatments on activation of hypothalamic nuclei.. Drugs were given into the NAcS of rats and food intake quantified during the next 4 h. In other groups, after the same treatments the brains were processed for c-Fos immunohistochemistry with focus on hypothalamic nuclei. Additional groups were used to quantify endocannabinoid levels in the nucleus accumbens and the hypothalamus after AA5HT and OMDM-1 intra-NAcS injections.. Our results indicate that the above treatments stimulate food intake during 4 h post-injection. They also increase c-Fos immunoreactivity in hypothalamic nuclei. The CB(1) antagonist, AM251, blocked these effects. Finally, we found elevated levels of 2-AG, but not anandamide, after intra-NAcS injections of AA5HT.. These data support the involvement of the endocannabinoid system in feeding behavior at the level of the NAcS and hypothalamus. In addition, this is the first experimental demonstration that the pharmacological inhibition of endocannabinoid inactivation in the NAcS stimulates food intake, suggesting that the endocannabinoid degrading proteins can be a target for treating eating disorders.

Topics: Amidohydrolases; Animals; Arachidonic Acids; Arcuate Nucleus of Hypothalamus; Benzyl Compounds; Cannabinoid Receptor Modulators; Eating; Endocannabinoids; Glycerides; Hypothalamus; Immunohistochemistry; Male; Nucleus Accumbens; Piperidines; Polyunsaturated Alkamides; Proto-Oncogene Proteins c-fos; Pyrazoles; Rats; Rats, Wistar; Receptor, Cannabinoid, CB1; Serotonin; Time Factors

In this study, we investigated the mechanism of S100B neurotoxicity and the effect of cannabinoids, in C6 cells treated with 1-methyl-4-phenyl 1,2,3,6 tetrahydropyridine (MPTP) and co-cultured with differentiated PC12 cells. MPTP concentration- and time-dependently increased S100B density in C6 cells. This effect was followed by increased C6 cell proliferation and decreased cell viability of co-cultured PC12 cells. An antibody against S100B, given to PC12 cells before co-culture, led to their survival. Treatment with arachidonyl-2-chloroethylamide, a CB1 agonist, significantly inhibited MPTP-induced S100B density in C6 cells and protected co-cultured PC12 cells from cell death. Because MPTP selectively increased the levels of anandamide in C6 cells, the involvement of the endocannabinoid system was investigated by using selective inhibitors of endocannabinoid inactivation (cellular re-uptake or enzymatic hydrolysis) and selective cannabinoid CB1 and CB2 receptor antagonists and by silencing the CB1 receptor. Our data suggest that selective activation of CB1 receptors by either exogenous or endogenous cannabinoids might afford neuroprotection in MPTP-induced neurotoxicity also by controlling S100B up-regulation in activated glial cells.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Amidohydrolases; Animals; Antibodies; Apoptosis; Arachidonic Acids; Calcium; Caspase 3; Cell Communication; Cell Differentiation; Cell Proliferation; Cell Survival; Coculture Techniques; Culture Media, Conditioned; Dose-Response Relationship, Drug; Endocannabinoids; Enzyme Activation; Enzyme Inhibitors; Indoles; MPTP Poisoning; Nerve Growth Factors; Neuroglia; Neurons; Neuroprotective Agents; PC12 Cells; Piperidines; Polyunsaturated Alkamides; Pyrazoles; Rats; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Rimonabant; RNA Interference; RNA, Small Interfering; S100 Calcium Binding Protein beta Subunit; S100 Proteins; Serotonin; Time Factors; Up-Regulation

Recent work in our laboratories has demonstrated that an opioid-independent form of stress-induced analgesia (SIA) is mediated by endogenous cannabinoids [Hohmann et al., 2005. Nature 435, 1108]. Non-opioid SIA, induced by a 3-min continuous foot shock, is characterized by the mobilization of two endocannabinoid lipids--2-arachidonoylglycerol (2-AG) and anandamide--in the midbrain periaqueductal gray (PAG). The present studies were conducted to examine the contributions of spinal endocannabinoids to nonopioid SIA. Time-dependent increases in levels of 2-AG, but not anandamide, were observed in lumbar spinal cord extracts derived from shocked relative to non-shocked rats. Notably, 2-AG accumulation was of smaller magnitude than that observed previously in the dorsal midbrain following foot shock. 2-AG is preferentially degraded by monoacylglycerol lipase (MGL), whereas anandamide is hydrolyzed primarily by fatty-acid amide hydrolase (FAAH). This metabolic segregation enabled us to manipulate endocannabinoid tone at the spinal level to further evaluate the roles of 2-AG and anandamide in nonopioid SIA. Intrathecal administration of the competitive CB1 antagonist SR141716A (rimonabant) failed to suppress nonopioid SIA, suggesting that supraspinal rather than spinal CB1 receptor activation plays a pivotal role in endocannabinoid-mediated SIA. By contrast, spinal inhibition of MGL using URB602, which selectively inhibits 2-AG hydrolysis in the PAG, enhanced SIA through a CB1-selective mechanism. Spinal inhibition of FAAH, with either URB597 or arachidonoyl serotonin (AA-5-HT), also enhanced SIA through a CB1-mediated mechanism, presumably by increasing accumulation of tonically released anandamide. Our results suggest that endocannabinoids in the spinal cord regulate, but do not mediate, nonopioid SIA.

Topics: Analgesia; Analysis of Variance; Animals; Arachidonic Acids; Behavior, Animal; Benzamides; Carbamates; Dose-Response Relationship, Drug; Drug Interactions; Endocannabinoids; Glycerides; Male; Mass Spectrometry; Pain Measurement; Piperidines; Polyunsaturated Alkamides; Pyrazoles; Rats; Rats, Sprague-Dawley; Reaction Time; Rimonabant; Serotonin; Spinal Cord; Stress, Psychological; Time Factors

Endocannabinoid signaling has been shown to be enhanced in several cancer tissues and malignant cells, and studies in cell lines have shown that this up-regulation might serve the purpose of providing transformed cells with a further means to inhibit their proliferation. Here we investigated the effect of inhibitors of endocannabinoid degradation on the growth of rat thyroid tumor xenografts induced in athymic mice. VDM-11, a selective inhibitor of endocannabinoid cellular re-uptake, and arachidonoyl-serotonin (AA-5-HT), a selective blocker of endocannabinoid enzymatic hydrolysis, both inhibited the growth in vivo of tumor xenografts induced by the subcutaneous injection of rat thyroid transformed (KiMol) cells. This effect was accompanied by significantly enhanced endocannabinoid concentrations in the tumors excised at the end of the in vivo experiments. Endocannabinoids, as well as VDM-11 and AA-5-HT, inhibited the growth in vitro of the transformed rat thyroid cells used to induce the tumors in vivo, and their effect was reversed at least in part by the cannabinoid CB1 receptor antagonist SR141716A. This compound, however, when administered alone, did not enhance, but instead slightly inhibited, the growth of rat thyroid transformed cells both in vitro and in tumor xenografts induced in vivo. These findings indicate that endocannabinoids tonically control tumor growth in vivo by both CB1-mediated and non-CB1-mediated mechanisms and that, irrespective of the molecular mechanism of their anti-proliferative action, inhibitors of their inactivation might be used for the development of novel anti-cancer drugs.

Topics: Animals; Arachidonic Acids; Biodegradation, Environmental; Cannabinoid Receptor Modulators; Cell Proliferation; Endocannabinoids; Mice; Mice, Nude; Piperidines; Pyrazoles; Rats; Receptor, Cannabinoid, CB1; Rimonabant; Serotonin; Thyroid Neoplasms; Xenograft Model Antitumor Assays