jhw-015 and arachidonyl-2-chloroethylamide

Interstitial cystitis is a debilitating bladder inflammation disorder. To date, the understanding of the causes of interstitial cystitis remains largely fragmentary and there is no effective treatment available. Recent experimental results have shown a functional role of the endocannabinoid system in urinary bladder. In this study, we evaluated the anti-inflammatory effect of selective cannabinoid CB1 and CB2 receptor agonists in a mouse model of interstitial cystitis. Bladder inflammation was induced in mice by lipopolysaccharide (LPS) and whole bladders were removed 24h later. LPS induced a significant increase of the contractile amplitude in spontaneous activity and a hypersensitivity to exogenous acetylcholine-induced contraction of whole-isolated bladder. Next, we evaluated the anti-inflammatory activity of cannabinoidergic compounds by pretreating mice with CB1 or CB2 selective agonist compounds, respectively ACEA and JWH015. Interestingly, JWH015, but not ACEA, antagonized LPS-induced bladder inflammation. Additionally, anti-inflammatory activity was studied by evaluation, leukocytes mucosa infiltration, myeloperoxidase activity, and mRNA expression of pro-inflammatory interleukin (IL-1α and IL-1β), tumor necrosis factor-alpha (TNF-α) and cannabinoid CB1 and CB2 receptors. JWH015 significantly decreased leukocytes infiltration in both submucosa and mucosa, as well as the myeloperoxydase activity, in LPS treated mice. JWH015 reduced mRNA expression of IL-1α, IL-1β, and TNF-α. LPS treatment increased expression of bladder CB2 but not CB1 mRNA. Taken together, these findings strongly suggest that modulation of the cannabinoid CB2 receptors might be a promising therapeutic strategy for the treatment of bladder diseases and conditions characterized by inflammation, such as interstitial cystitis.

Topics: Animals; Arachidonic Acids; Cannabinoids; Cystitis, Interstitial; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Indoles; Lipopolysaccharides; Male; Mice; Organ Culture Techniques; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2

Cannabinoids have been widely reported to have neuroprotective properties in vitro and in vivo. In this study we compared the effects of CB1 and CB2 receptor-selective ligands, the endocannabinoid anandamide and the phytocannabinoid cannabidiol, against oxidative stress and the toxic hallmark Alzheimer's protein, β-amyloid (Aβ) in neuronal cell lines. PC12 or SH-SY5Y cells were selectively exposed to either hydrogen peroxide, tert-butyl hydroperoxide or Aβ, alone or in the presence of the CB1 specific agonist arachidonyl-2'-chloroethylamide (ACEA), CB2 specific agonist JWH-015, anandamide or cannabidiol. Cannabidiol improved cell viability in response to tert-butyl hydroperoxide in PC12 and SH-SY5Y cells, while hydrogen peroxide-mediated toxicity was unaffected by cannabidiol pretreatment. Aβ exposure evoked a loss of cell viability in PC12 cells. Of the cannabinoids tested, only anandamide was able to inhibit Aβ-evoked neurotoxicity. ACEA had no effect on Aβ-evoked neurotoxicity, suggesting a CB1 receptor-independent effect of anandamide. JWH-015 pretreatment was also without protective influence on PC12 cells from either pro-oxidant or Aβ exposure. None of the cannabinoids directly inhibited or disrupted preformed Aβ fibrils and aggregates. In conclusion, the endocannabinoid anandamide protects neuronal cells from Aβ exposure via a pathway unrelated to CB1 or CB2 receptor activation. The protective effect of cannabidiol against oxidative stress does not confer protection against Aβ exposure, suggesting divergent pathways for neuroprotection of these two cannabinoids.

Topics: Amyloid beta-Peptides; Analysis of Variance; Animals; Antioxidants; Arachidonic Acids; Benzothiazoles; Cannabinoids; Cell Line, Tumor; Cell Survival; Chromans; Drug Interactions; Gene Expression Regulation; Humans; Hydrogen Peroxide; Indoles; Lipid Peroxidation; Microscopy, Electron, Transmission; Neuroblastoma; Oxidative Stress; PC12 Cells; Peptide Fragments; Rats; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Thiazoles

Pain associated with musculoskeletal disorders can be difficult to control and the incorporation of new approaches for its treatment is an interesting challenge. Activation of cannabinoid (CB) receptors decreases nociceptive transmission in acute, inflammatory and neuropathic pain states; however, although the use of cannabis derivatives has been recently accepted as a useful alternative for the treatment of spasticity and pain in patients with multiple sclerosis, the effects of CB receptor agonists in muscular pain have hardly been studied.. Here, we characterized the antinociceptive effect of non selective and selective CB agonists by systemic and local administration, in two muscular models of pain, masseter and gastrocnemius, induced by hypertonic saline (HS) injection. Drugs used were: the non-selective agonist WIN 55,212-2 and two selective agonists, ACEA (CB 1) and JWH 015 (CB 2); AM 251 (CB 1) and AM 630 (CB 2) were used as selective antagonists.. In the masseter pain model, both systemic (intraperitoneal) and local (intramuscular) administration of CB 1 and CB 2 agonists reduced the nociceptive behaviour induced by HS, whereas in the gastrocnemius model the local administration was more effective than systemic.. Our results provide evidence that both, CB 1 and CB 2 receptors can contribute to muscular antinociception and, interestingly, suggest that the local administration of CB agonists could be a new and useful pharmacological strategy in the treatment of muscular pain, avoiding adverse effects induced by systemic administration.

Topics: Animals; Arachidonic Acids; Behavior, Animal; Benzoxazines; Cannabinoid Receptor Agonists; Cannabinoid Receptor Antagonists; Indoles; Male; Morpholines; Motor Activity; Musculoskeletal Pain; Naphthalenes; Pain Measurement; Piperidines; Pyrazoles; Rats; Rats, Wistar; Treatment Outcome

Endocannabinoid lipids are known to exert orexigenic effects via central cannabinoid CB1 and CB2 receptors, which have also been identified in islet endocrine cells. However, there is no consensus on whether the receptors are expressed by beta-cells, nor what effect CB1 and CB2 receptor agonists have on insulin secretion. In the current study we have therefore used the mouse MIN6 beta-cell line rather than primary islets, which are heterogeneous clusters of endocrine cells. Cannabinoid receptor and diacylglycerol lipase isoform mRNAs were detected in MIN6 cells by RT-PCR and immunocytochemistry was used to identify cannabinoid receptor expression by MIN6 cells. Changes in cyclic AMP and intracellular calcium were measured by immunoassay and microfluorimetry, respectively, and insulin secretion from perifused MIN6 pseudoislets was determined by radioimmunoassay. MIN6 beta-cells express the cannabinoid synthesising enzyme diacylglycerol lipase and CB1 and CB2 receptors, which are coupled to inhibition of beta-cell cyclic AMP generation and stimulation of intracellular calcium levels. Cannabinoid receptor activation with pharmacological agonists resulted in reversible elevations in insulin secretion at both 2 mM and 20 mM glucose. Synthesis of endocannabinoids by beta-cells may provide an additional mechanism for stimulation of insulin secretion through activation of beta-cell CB1 and/or CB2 cannabinoid receptors.

Topics: Animals; Arachidonic Acids; Calcium; Cell Line; Cyclic AMP; Glucose; Indoles; Insulin; Insulin Secretion; Insulin-Secreting Cells; Lipoprotein Lipase; Mice; Protein Isoforms; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; RNA, Messenger

Chronic inflammatory conditions, such as granulomas, are associated with angiogenesis. Mast cells represent the main cell type orchestrating angiogenesis, through the release of their granule content. Therefore, compounds able to modulate mast cell behaviour may be considered as a new pharmacological approach to treat angiogenesis-dependent events. Here, we tested the effect of selective cannabinoid (CB) receptor agonists in a model of angiogenesis-dependent granuloma formation induced by lambda-carrageenin in rats.. Granulomas were induced by lambda-carrageenin-soaked sponges implanted subcutaneously on the back of male Wistar rats. After 96 h, implants were removed and granuloma formation was measured (wet weight); angiogenesis was evaluated by histological analysis and by the measurement of haemoglobin content. Mast cells in the granulomas were evaluated histologically and by RT-PCR and immunoblotting analysis for mast cell-derived proteins (rat mast cell protease-5 (rMCP-5) and nerve growth factor). Selective CB1 and CB2 receptor agonists(,) ACEA and JWH-015 (0.001-0.1 mg mL(-1)), were given locally only once, at the time of implantation.. The CB1 and CB2 receptor agonists decreased the weight and vascularization of granulomas after 96 h. This treatment also reduced mast cell number and activation in granulomatous tissue. Specifically, these compounds prevented the transcription and expression of rMCP-5, a protein involved in sprouting and advance of new blood vessels.. Modulation of mast cell function by cannabinoids reduced granuloma formation and associated angiogenesis. Therefore cannabinoid-related drugs may be useful in the management of granulomatous diseases accompanied by angiogenesis.

Topics: Animals; Arachidonic Acids; Carrageenan; Chymases; Dose-Response Relationship, Drug; Gene Expression Regulation, Enzymologic; Granuloma; Indoles; Male; Mast Cells; Neovascularization, Pathologic; Rats; Rats, Wistar; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Transcription, Genetic

It is well accepted that endogenous cannabinoids and CB1 receptors are involved in the regulation of smooth muscle contractility and intestinal motility, through a mechanism mainly related to reduction of acetylcholine release from cholinergic nerve endings. Because, few data exist on a possible modulatory action of the cannabinoid agents on the non-adrenergic non-cholinergic (NANC) excitatory and inhibitory neurotransmission, the aim of the present study was to investigate the effects of cannabinoid drugs on the NANC responses elicited by electrical field stimulation (EFS) in the circular muscle of mouse proximal colon. Colonic contractions were monitored as changes in endoluminal pressure. In NANC conditions, EFS evoked TTX-sensitive responses, characterized by a relaxation, nitrergic in origin, followed by a contraction. The EFS-evoked contraction was significantly reduced by SR48968, NK2 receptor antagonist, and abolished by co-administration of SR48968 and SR140333, NK1 receptor antagonist, suggesting that it was due to release of tachykinins. The cannabinoid receptor synthetic agonist, WIN55,212-2, the putative endogenous ligand, anandamide, the selective CB1 receptor agonist ACEA, but not the selective CB2 receptor agonist JWH-015, produced a concentration-dependent reduction of the NANC contractile responses, without affecting the NANC relaxation. ACEA or anandamide did not modify the contractions induced by exogenous [beta-Ala(8)]-NKA(4-10), agonist of NK2 receptors. The selective antagonist of CB1 receptors, SR141716A, per se failed to affect the EFS-evoked responses, but antagonized the inhibitory effects of WIN55,212-2, anandamide and ACEA on NANC contractile responses. AM630, CB2 receptor antagonist, did not modify the inhibitory effects of WIN55,212-2 or anandamide. URB597, inhibitor of the fatty acid amide hydrolase, enzyme which catalyze the hydrolysis of anandamide, was without any effect on the NANC evoked responses. We conclude that the activation of prejunctional CB1 receptors produces inhibition of NANC contractile responses in mouse colonic preparations. However, endogenous ligands do not seem to modulate tonically the NANC transmission in mouse colon.

Topics: Animals; Arachidonic Acids; Benzoxazines; Cannabinoid Receptor Modulators; Cannabinoids; Colon; Dose-Response Relationship, Drug; Electric Stimulation; Endocannabinoids; Enteric Nervous System; Excitatory Postsynaptic Potentials; Gastrointestinal Motility; In Vitro Techniques; Indoles; Inhibitory Postsynaptic Potentials; Mice; Mice, Inbred C57BL; Morpholines; Naphthalenes; Neuromuscular Junction; Piperidines; Polyunsaturated Alkamides; Pyrazoles; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Receptors, Tachykinin; Rimonabant; Synaptic Transmission; Tachykinins

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

While most of the studies concerning the role of cannabinoids on gastric motility have focused the attention on the gastric emptying in in vivo animal models, there is little information about the cannabinoid peripheral influence in the stomach. In addition, the functional features of CB2 receptors in the gastrointestinal tract have been poorly characterized. The purpose of the present study was to investigate the effects of cannabinoid drugs on the excitatory cholinergic and inhibitory non-adrenergic non-cholinergic (NANC) neurotransmission in mouse isolated gastric preparations. Intraluminal pressure from isolated whole stomach was recorded and mechanical responses induced by electrical field stimulation (EFS) were analyzed in different experimental conditions. EFS (0.5ms duration, supramaximal voltage, in trains of 5s, 2-16Hz) caused a cholinergic contraction, which was abolished by atropine or tetrodotoxin (TTX). The cannabinoid receptor agonist, WIN 55,212-2, the endogenous ligand, anandamide, the selective CB1 receptor agonist ACEA, and the selective CB2 receptor agonists, JWH015 and JWH133, produced a concentration-dependent reduction of the EFS-evoked cholinergic contractions. SR141716A, CB1 receptor antagonist, significantly attenuated the inhibitory effects induced by WIN 55,212-2, anandamide or ACEA, without affecting those caused by JWH133. AM630, CB2 receptor antagonist, reduced the inhibitory effects induced by WIN 55,212-2, anandamide, JWH015 or JWH133, without affecting those caused by ACEA. The joint application of SR141716A and AM630 was able of fully preventing the WIN 55,212-2 and anandamide actions. The cannabinoid antagonists failed per se to affect the neurally evoked responses. Cannabinoids did not modify the contractions produced by exogenous carbachol. In the presence of atropine and guanethidine (NANC conditions) EFS-induced TTX-sensitive relaxation consisting in an early and rapid component followed by a second slow phase, which were unaffected by cannabinoid drugs. In conclusion, the present results suggest that cannabinoids play a prejunctional modulatory role on the cholinergic excitatory transmission without affecting the NANC inhibitory transmission. In addition, this study provides experimental evidence that also the activation of CB2 receptors is able to reduce cholinergic neurotransmission in the mouse stomach.

Topics: Animals; Arachidonic Acids; Benzoxazines; Cannabinoid Receptor Modulators; Cannabinoids; Cholinergic Fibers; Electric Stimulation; Endocannabinoids; Excitatory Postsynaptic Potentials; Gastrointestinal Motility; In Vitro Techniques; Indoles; Inhibitory Postsynaptic Potentials; Male; Mice; Mice, Inbred C57BL; Morpholines; Naphthalenes; Neuromuscular Junction; Piperidines; Polyunsaturated Alkamides; Pyrazoles; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Receptors, Presynaptic; Rimonabant; Stomach; Synaptic Transmission

The aim of the present study was to document the presence of cannabinoid receptors in the rat heart, and to assess the cardioprotective properties of CB(1)- and CB(2)-receptor agonists. Rat isolated hearts were exposed to low-flow ischemia and reperfusion, with selective cannabinoid agonists administered prior to and during the ischemic period. In some hearts, RT-PCR, Western blots, and immunohistological techniques were used to identify and localize both cannabinoid-receptor subtypes. The effect of cannabinoids on infarct size was evaluated in additional hearts using TTC staining. Protein and mRNA for both CB(1)- and CB(2)-receptors were found in rat heart extracts. CB(1)-receptors were localized almost exclusively on arterial and capillary endothelial cells in intact hearts, whereas CB(2)-receptors appeared on cardiomyocytes and endothelial cells of larger arteries. Both the CB(1)-agonist, ACEA (50 nM), and the CB(2)-agonist, JWH015 (50 nM), reduced infarct size. However, only the cardioprotective effect of the CB(1)-agonist was blocked by the NO-synthase inhibitor, N(G)-nitro-L-arginine (30 microM). In conclusion, CB(1)-receptors are present mainly on endothelial cells in the rat heart, and exert their effect through production of NO. In contrast, CB(2)-receptors present on cardiomyocytes exert a cardioprotective effect independent of this endothelial factor.

Topics: Animals; Arachidonic Acids; Blotting, Western; Endothelium; Immunohistochemistry; In Vitro Techniques; Indoles; Male; Myocardial Infarction; Myocardium; Nitric Oxide; Nitric Oxide Synthase Type II; Rats; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Reverse Transcriptase Polymerase Chain Reaction; RNA

We have investigated the effects of cannabinoid agonists and antagonists on tumour necrosis factor-alpha (TNF-alpha)-induced secretion of interleukin-8 from the colonic epithelial cell line, HT-29. The cannabinoid receptor agonists [(-)-3-[2-hydroxy-4-(1,1-dimethyl-heptyl)-phenyl]4-[3-hydroxypropyl]cyclo-hexan-1-ol] (CP55,940); Delta-9-tetrahydrocannabinol; [R(+)-[2,3-dihydro-5-methyl-3-[(morpholinyl) methyl] pyrrolo[1,2,3-de]1,4-benzoxazin-6-yl](1-naphthyl) methanone mesylate] (WIN55,212-2) and 1-propyl-2-methyl-3-naphthoyl-indole (JWH 015) inhibited TNF-alpha induced release of interleukin-8 in a concentration-dependent manner. The less active enantiomer of WIN55212-2, [S(-)-[2,3-dihydro-5-methyl-3-[(morpholinyl)methyl]pyrrolo[1,2,3-de]1,4-benzoxazin-6-yl](1-naphthyl) methanone mesylate (WIN55212-3), and the cannabinoid CB(1) receptor agonist arachidonoyl-2-chloroethylamide (ACEA) had no significant effect on TNF-alpha-induced release of interleukin-8. The cannabinoid CB(1) receptor antagonist N-(piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1,4-pyrazole-3-carboxamide hydrochloride (SR141716A; 10(-6) M) antagonised the inhibitory effect of CP55,940 (pA(2)=8.3+/-0.2, n=6) but did not antagonise the inhibitory effects of WIN55212-2 and JWH 015. The cannabinoid CB(2) receptor antagonist N-(1,S)-endo1,3,3-trimethylbicyclo(2,2,1)heptan-2-yl)-5(4-chloro-3-methyl-phenyl)-1-(4-methylbenzyl)-pyrazole-3-carboxamide (SR144528; 10(-6) M) antagonised the inhibitory effects of CP55,940 (pA(2)=8.2+/-0.8, n=6), WIN55212-2 (pA(2)=7.1+/-0.3, n=6) and JWH 015 (pA(2)=7.6+/-0.3, n=6), respectively. Western immunoblotting of HT-29 cell lysates revealed a protein with a size that is consistent with the presence of cannabinoid CB(2) receptors. We conclude that in HT-29 cells, TNF-alpha-induced interleukin-8 release is inhibited by cannabinoids through activation of cannabinoid CB(2) receptors.

Topics: Arachidonic Acids; Benzoxazines; Camphanes; Cannabinoids; Cell Survival; Cyclohexanols; Dose-Response Relationship, Drug; HT29 Cells; Humans; Immunoblotting; Indoles; Interleukin-8; Kinetics; Morpholines; Naphthalenes; Piperidines; Pyrazoles; Receptors, Cannabinoid; Receptors, Drug; Rimonabant; Tumor Necrosis Factor-alpha

The effects of a range of cannabinoid receptor agonists and antagonists on phytohaemagglutinin-induced secretion of interleukin-2 from human peripheral blood mononuclear cells were investigated. The nonselective cannabinoid receptor agonist WIN55212-2 ((R)-(+)-[2,3-dihydro-5-methyl-3-[4-morpholinylmethyl]pyrrolo[1,2,3-de]1,4-benzoxazin-6-yl](1-naphthyl) methanone mesylate) and the selective cannabinoid CB(2) receptor agonist JWH 015 ((2-methyl-1-propyl-1H-indol-3-yl)-1-napthalenylmethanone) inhibited phytohaemagglutinin (10 microg/ml)-induced release of interleukin-2 in a concentration-dependent manner (IC(1/2max), WIN55212-2=8.8 x 10(-7) M, 95% confidence limits (C.L.)=2.2 x 10(-7)-3.5 x 10(-6) M; JWH 015=1.8 x 10(-6) M, 95% C.L.=1.2 x 10(-6)-2.9 x 10(-6) M, n=5). The nonselective cannabinoid receptor agonists CP55,940 ((-)-3-[2-hydroxy-4-(1,1-dimethyl-hepthyl)-phenyl]4-[3-hydroxypropyl]cyclo-hexan-1-ol), Delta(9)-tetrahydrocannabinol and the selective cannabinoid CB(1) receptor agonist ACEA (arachidonoyl-2-chloroethylamide) had no significant (P>0.05) inhibitory effect on phytohaemagglutinin-induced release of interleukin-2. Dexamethasone significantly (P<0.05) inhibited phytohaemagglutinin-induced release of interleukin-2 in a concentration-dependent manner (IC(1/2max)=1.3 x 10(-8) M, 95% C.L.=1.4 x 10(-9)-3.2 x 10(-8) M). The cannabinoid CB(1) receptor antagonist SR141716A (N-(piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide hydrochloride) (10(-6) M) did not antagonise the inhibitory effect of WIN55212-2 whereas the cannabinoid CB(2) receptor antagonist SR144528 (N-(1,S)-endo-1,3,3-trimethyl bicyclo(2,2,1)heptan-2-yl)-5-(4-chloro-3-methylphenyl)-1-(4-methylbenzyl)-pyrazole-3-carboxamide) antagonised the inhibitory effect of WIN55212-2 (pA(2)=6.3+/-0.1, n=5). In addition, CP55,940 (10(-6) M) and Delta(9)-tetrahydrocannabinol (10(-6) M) also antagonised the inhibitory effects of WIN55212-2 (pA(2)=6.1+/-0.1, n=5 and pA(2)=6.9+/-0.2, n=5). In summary, WIN55,212-2 and JWH 015 inhibited interleukin-2 release from human peripheral blood mononuclear cells via the cannabinoid CB(2) receptor. In contrast, CP55,940 and Delta(9)-tetrahydrocannabinol behaved as partial agonists/antagonists in these cells.

Topics: Arachidonic Acids; Benzoxazines; Camphanes; Cell Survival; Cyclohexanols; Dose-Response Relationship, Drug; Dronabinol; Humans; Indoles; Interleukin-2; Leukocytes, Mononuclear; Morpholines; Naphthalenes; Phytohemagglutinins; Piperidines; Pyrazoles; Receptors, Cannabinoid; Receptors, Drug; Rimonabant