3-(2-hydroxy-4-(1-1-dimethylheptyl)phenyl)-4-(3-hydroxypropyl)cyclohexanol and Weight-Gain

Body weight gain is a common side effect of treatment with antipsychotics, but the mechanisms underlying this weight gain are unknown. Several factors may be involved in antipsychotic-induced body weight gain including the cannabinoid receptor 1 (CB(1)), the serotonin receptor 2C, the ghrelin receptor, neuropeptide Y, adiponectin and proopiomelanocortin. We investigated whether the expression of these factors was affected in rats chronically treated with the antipsychotic risperidone.. Male Sprague-Dawley rats were treated with risperidone (1.0 mg/kg/day) or vehicle (20% hydroxypropyl beta-cyclodextrin) for 28 days. Expression of the aforementioned factors were examined together with plasma prolactin and ghrelin levels.. No difference in body weight gained during treatment was observed between risperidone and vehicle treated rats, but plasma risperidone levels positively correlated with visceral fat mass. Risperidone treatment increased CB(1) receptor binding in the arcuate nucleus (40%), hippocampus (25-30%) and amygdala (35%) without concurrent alterations in the CB(1) receptor mRNA. Risperidone treatment increased adiponectin mRNA.. The present study showed that risperidone treatment altered CB(1) receptor binding in the rat brain. Risperidone-induced adiposity and metabolic dysfunction in the clinic may be explained by increased CB(1) receptor density in brain regions involved in appetite and regulation of metabolic function.

Topics: Adiponectin; Animals; Antipsychotic Agents; Brain; Cyclohexanols; Dopamine Antagonists; Eating; Ghrelin; Male; Motor Activity; Neuropeptide Y; Pro-Opiomelanocortin; Prolactin; Protein Binding; Raclopride; Rats; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB1; Receptor, Serotonin, 5-HT2C; Receptors, Dopamine D2; Receptors, Ghrelin; Risperidone; RNA, Messenger; Tritium; Weight Gain

Some atypical antipsychotics clinically used to treat schizophrenia induce weight gain by unknown mechanisms. The dorsal vagal complex (DVC) of the brainstem and the endogenous cannabinoid system are implicated in the regulation of appetite signalling and food intake. We investigated whether antipsychotic drugs alter cannabinoid receptor-binding density in the DVC. Female Spraguewk (short-term) or 120.83, p=0.01). In addition, only chronic olanzapine treatment increased food intake. These results show that olanzapine, an antipsychotic with a high risk of weight gain as a side-effect, significantly decreased cannabinoid receptor binding in the DVC, whilst aripiprazole and haloperidol, antipsychotics with a low risk of weight gain had little or no effect on binding. These results suggest that a mechanism for antipsychotic-induced weight gain may be through the modulation of cannabinoid receptors in the DVC.

Topics: Animals; Antipsychotic Agents; Autoradiography; Benzodiazepines; Binding, Competitive; Cyclohexanols; Female; Immunosuppressive Agents; Medulla Oblongata; Olanzapine; Protein Binding; Rats; Rats, Sprague-Dawley; Receptors, Cannabinoid; Tritium; Weight Gain

LH-21 (5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-3-hexyl-1H-1,2,4-triazole) was previously reported as a neutral antagonist at the cannabinoid CB1 receptor which, despite its reported poor ability to penetrate into the brain, suppressed food intake and body weight in rats by intraperitoneal administration. In the present study, we studied the mechanism of action of LH-21 by characterizing its in vitro pharmacological properties and in vivo efficacy. LH-21 inhibited the binding of [3H]CP55940 to cloned human and rat CB1 receptors with IC50 values of 631+/-98 nM, and 690+/-41 nM, respectively, and acted as an inverse agonist in a cAMP functional assay using cultured cells expressing human, rat or mouse CB1 receptor. The compound was shown to be brain-penetrant in rats by intravenous administration. Importantly, a single dose of LH-21 (60 mg/kg, i.p.) caused a similar suppression of overnight food intake and body weight gain in wild-type and CB1 receptor knockout mice. Our results suggest that LH-21 is a low affinity inverse agonist for the CB1 receptor and does not act on the CB1 receptor to inhibit food intake in mice.

Topics: Animals; Anti-Obesity Agents; Binding, Competitive; Blood-Brain Barrier; CHO Cells; Cricetinae; Cricetulus; Cyclic AMP; Cyclohexanols; Dose-Response Relationship, Drug; Drug Inverse Agonism; Eating; Humans; Injections, Intraperitoneal; Injections, Intravenous; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Protein Binding; Radioligand Assay; Rats; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Recombinant Proteins; Transfection; Triazoles; Weight Gain

Rimonabant (Acomplia, SR141716A), a cannabinoid CB1 receptor inverse agonist, has recently been approved for the treatment of obesity. There are, however, concerns regarding its side effect profile. Developing a CB1 antagonist with a different pharmacological mechanism may lead to a safer alternative. To this end we have screened a proprietary small molecule library and have discovered a novel class of allosteric antagonist at CB1 receptors. Herein, we have characterized an optimized prototypical molecule, PSNCBAM-1, and its hypophagic effects in vivo.. A CB1 yeast reporter assay was used as a primary screen. PSNCBAM-1 was additionally characterized in [35S]-GTPgammaS, cAMP and radioligand binding assays. An acute rat feeding model was used to evaluate its effects on food intake and body weight in vivo.. In CB1 receptor yeast reporter assays, PSNCBAM-1 blocked the effects induced by agonists such as CP55,940, WIN55212-2, anandamide (AEA) or 2-arachidonoyl glycerol (2-AG). The antagonist characteristics of PSNCBAM-1 were confirmed in [35S]-GTPgammaS binding and cAMP assays and was shown to be non-competitive by Schild analyses. PSNCBAM-1 did not affect CB2 receptors. In radioligand binding assays, PSNCBAM-1 increased the binding of [3H]CP55,940 despite its antagonist effects. In an acute rat feeding model, PSNCBAM-1 decreased food intake and body weight.. PSNCBAM-1 exerted its effects through selective allosteric modulation of the CB1 receptor. The acute effects on food intake and body weight induced in rats provide a first report of in vivo activity for an allosteric CB1 receptor antagonist.

Topics: Allosteric Regulation; Animals; Appetite Depressants; Cell Line; Cell Membrane; Cerebral Cortex; Cyclic AMP; Cyclohexanols; Dose-Response Relationship, Drug; Eating; Guanosine 5'-O-(3-Thiotriphosphate); Humans; Male; Molecular Structure; Phenylurea Compounds; Piperidines; Pyrazoles; Pyridines; Radioligand Assay; Rats; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB1; Rimonabant; Saccharomyces cerevisiae; Silicone Elastomers; Sulfur Radioisotopes; Weight Gain

Cannabis is widely abused by women at reproductive age and during pregnancy. Animal studies showed a particular vulnerability of the developing brain to prenatal chronic cannabinoid administration. We determined whether prenatal exposure to WIN 55,212-2, a potent cannabinoid receptor agonist, affected (1) density, affinity and/or function of cannabinoid CB(1) receptors, (2) endogenous levels of the endocannabinoid anandamide, (3) activities of the major anandamide synthesising and hydrolysing enzymes, N-acyl-phosphatidylethanolamine-specific phospholipase D (NAPE-PLD) and fatty acid amide hydrolase (FAAH), respectively, in brain areas of adult male offspring rats. Furthermore, the effect of prenatal WIN 55,212-2 on spontaneous motility was analyzed. Pregnant rats were treated daily with WIN 55,212-2 (0.5 mg/kg, gestation day 5-20) or vehicle. [(3)H]CP 55,940 and WIN 55,212-2-stimulated [(35)S] GTPgammaS binding were carried out in cerebellum, cerebral cortex, hippocampus, striatum and limbic areas of male adult offspring. Levels of anandamide, FAAH and NAPE-PLD activity were also determined. EC(50) values for WIN 55,212-2-stimulated [(35)S]GTPgammaS binding were significantly different in hippocampus (-26%) and striatum (+27%) in WIN 55,212-2-treated rats. Cannabinoid CB(1) receptor density and affinity were not affected in any analyzed region. In the striatum, increased anandamide levels were associated with reduced FAAH and enhanced NAPE-PLD activities. Opposite changes in anandamide levels and enzymatic activities were detected in limbic areas of WIN 55,212-2-treated rats. Ambulatory activity between WIN 55,212-2- and vehicle-treated adult offspring did not vary. Our results show that prenatal exposure to cannabinoid agonist induces a long-term alteration of endocannabinoid system in brain areas involved in learning-memory, motor activity and emotional behavior.

Topics: Analgesics; Animals; Arachidonic Acids; Behavior, Animal; Benzoxazines; Binding, Competitive; Brain; Cannabinoid Receptor Agonists; Cannabinoid Receptor Modulators; Cyclohexanols; Dose-Response Relationship, Drug; Endocannabinoids; Female; Guanosine 5'-O-(3-Thiotriphosphate); Litter Size; Male; Morpholines; Motor Activity; Naphthalenes; Phospholipase D; Polyunsaturated Alkamides; Pregnancy; Prenatal Exposure Delayed Effects; Radioligand Assay; Rats; Rats, Wistar; Receptor, Cannabinoid, CB1; Receptors, Cannabinoid; Sulfur Radioisotopes; Weight Gain