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Carai MAM, Colombo G, Gessa GL. Rimonabant: The first therapeutically relevant cannabinoid antagonist. Life Sci 2005; 77:2339-50. [PMID: 15935395 DOI: 10.1016/j.lfs.2005.04.017] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2005] [Accepted: 04/01/2005] [Indexed: 10/25/2022]
Abstract
The present paper synthetically reviews the multiple experimental lines of evidence indicating the ability of the prototypic cannabinoid CB(1) receptor antagonist, rimonabant (also known as SR 141716), to suppress the reinforcing/rewarding properties of different drugs of abuse, including cocaine, heroin, nicotine and alcohol, in laboratory rodents. This paper also reviews the data demonstrating that rimonabant reduces food intake and body weight in laboratory animals and humans. Taken together, the data reviewed here suggest that rimonabant may constitute a new and potentially effective medication for the treatment of drug addiction and obesity-related disorders.
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Affiliation(s)
- Mauro A M Carai
- Bernard B. Brodie Department of Neuroscience, University of Cagliari, Viale Diaz 182, I-09126 Cagliari (CA), Italy.
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152
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Osei-Hyiaman D, DePetrillo M, Pacher P, Liu J, Radaeva S, Bátkai S, Harvey-White J, Mackie K, Offertáler L, Wang L, Kunos G. Endocannabinoid activation at hepatic CB1 receptors stimulates fatty acid synthesis and contributes to diet-induced obesity. J Clin Invest 2005; 115:1298-305. [PMID: 15864349 PMCID: PMC1087161 DOI: 10.1172/jci23057] [Citation(s) in RCA: 349] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2004] [Accepted: 02/15/2005] [Indexed: 01/12/2023] Open
Abstract
Endogenous cannabinoids acting at CB(1) receptors stimulate appetite, and CB(1) antagonists show promise in the treatment of obesity. CB(1) (-/-) mice are resistant to diet-induced obesity even though their caloric intake is similar to that of wild-type mice, suggesting that endocannabinoids also regulate fat metabolism. Here, we investigated the possible role of endocannabinoids in the regulation of hepatic lipogenesis. Activation of CB(1) in mice increases the hepatic gene expression of the lipogenic transcription factor SREBP-1c and its targets acetyl-CoA carboxylase-1 and fatty acid synthase (FAS). Treatment with a CB(1) agonist also increases de novo fatty acid synthesis in the liver or in isolated hepatocytes, which express CB(1). High-fat diet increases hepatic levels of the endocannabinoid anandamide (arachidonoyl ethanolamide), CB(1) density, and basal rates of fatty acid synthesis, and the latter is reduced by CB(1) blockade. In the hypothalamus, where FAS inhibitors elicit anorexia, SREBP-1c and FAS expression are similarly affected by CB(1) ligands. We conclude that anandamide acting at hepatic CB(1) contributes to diet-induced obesity and that the FAS pathway may be a common molecular target for central appetitive and peripheral metabolic regulation.
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Affiliation(s)
- Douglas Osei-Hyiaman
- National Institute on Alcohol Abuse & Alcoholism, NIH, Bethesda, Maryland 20892, USA
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153
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Di Marzo V, Matias I. Endocannabinoid control of food intake and energy balance. Nat Neurosci 2005; 8:585-9. [PMID: 15856067 DOI: 10.1038/nn1457] [Citation(s) in RCA: 525] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2005] [Accepted: 02/21/2005] [Indexed: 01/27/2023]
Abstract
Marijuana and its major psychotropic component, Delta(9)-tetrahydrocannabinol, stimulate appetite and increase body weight in wasting syndromes, suggesting that the CB(1) cannabinoid receptor and its endogenous ligands, the endocannabinoids, are involved in controlling energy balance. The endocannabinoid system controls food intake via both central and peripheral mechanisms, and it may also stimulate lipogenesis and fat accumulation. Here we discuss the multifaceted regulation of energy homeostasis by endocannabinoids, together with its applications to the treatment of eating disorders and metabolic syndromes.
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Affiliation(s)
- Vincenzo Di Marzo
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, Consiglio Nazionale delle Ricerche, Via Campi Flegrei 34, 80078, Pozzuoli, Naples, Italy.
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154
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Cooper SJ. Endocannabinoids and food consumption: comparisons with benzodiazepine and opioid palatability-dependent appetite. Eur J Pharmacol 2005; 500:37-49. [PMID: 15464019 DOI: 10.1016/j.ejphar.2004.07.009] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/01/2004] [Indexed: 01/22/2023]
Abstract
The endocannabinoid system consists of several endogenous lipids, including anandamide and 2-arachidonoyl-glycerol (2-AG), and constitute a retrograde signalling system, which modulates neurotransmitter release and synaptic plasticity. Specific brain-type cannabinoid receptors (CB(1)) are widely distributed in the central nervous system, and are localized presynaptically. Mounting evidence, reviewed here, indicates that cannabinoids can act to increase food consumption, and cannabinoid CB(1) receptor antagonists/inverse agonists reduce food intake and suppress operant responding for food rewards. Hence, endocannabinoids provide the first example of a retrograde signalling system, which is strongly implicated in the control of food intake. Benzodiazepine and opioid palatability-dependent appetite are well-established processes supported by several sources of convergent evidence; they provide pharmacological benchmarks against which to evaluate the endocannabinoids. To date, evidence that endocannabinoids specifically modulate palatability as an affective evaluative process is insufficient and not compelling. Endocannabinoids may have important clinical utility in the treatment of human obesity and forms of eating disorders.
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Affiliation(s)
- Steven J Cooper
- Kissileff Laboratory for the Study of Human Ingestive Behaviour, School of Psychology, University of Liverpool, Liverpool L69 7ZA, UK.
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155
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Lavey BJ, Kozlowski JA, Hipkin RW, Gonsiorek W, Lundell DJ, Piwinski JJ, Narula S, Lunn CA. Triaryl bis-sulfones as a new class of cannabinoid CB2 receptor inhibitors: identification of a lead and initial SAR studies. Bioorg Med Chem Lett 2005; 15:783-6. [PMID: 15664857 DOI: 10.1016/j.bmcl.2004.11.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2004] [Revised: 11/01/2004] [Accepted: 11/01/2004] [Indexed: 10/26/2022]
Abstract
A novel class of cannabinoid CB2 receptor ligands is described. These triaryl bis-sulfones are nanomolar inhibitors of the CB2 receptor and show high selectivity over the cannabinoid CB1 receptor. One example of this new class decreases ligand-induced GTPgammaS binding to recombinant CB2 cell membranes, identifying the compound as a CB2-selective inverse agonist.
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Affiliation(s)
- Brian J Lavey
- Department of Chemistry, Schering-Plough Research Institute, 2015 Galloping Hill Road, K-15-1-1545, Kenilworth, NJ 07033-0539, USA.
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156
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Osei-Hyiaman D, DePetrillo M, Pacher P, Liu J, Radaeva S, Bátkai S, Harvey-White J, Mackie K, Offertáler L, Wang L, Kunos G. Endocannabinoid activation at hepatic CB1 receptors stimulates fatty acid synthesis and contributes to diet-induced obesity. J Clin Invest 2005. [DOI: 10.1172/jci200523057] [Citation(s) in RCA: 791] [Impact Index Per Article: 41.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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157
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Thornton-Jones ZD, Vickers SP, Clifton PG. The cannabinoid CB1 receptor antagonist SR141716A reduces appetitive and consummatory responses for food. Psychopharmacology (Berl) 2005; 179:452-60. [PMID: 15821957 DOI: 10.1007/s00213-004-2047-8] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2004] [Accepted: 09/21/2004] [Indexed: 10/26/2022]
Abstract
RATIONALE The CB1 receptor antagonist SR141716A reduces food intake in rats. This effect is likely to depend on modulation of reward related processes. OBJECTIVE To investigate the effects of SR141716A on responding for food under a second order instrumental task in which responding and consumption of food can be separated, and on Pavlovian responding for a stimulus predictive of food reward. METHODS Instrumental responding and pellet consumption following administration of SR141716A (0-3 mg/kg) were recorded under an FI5 min FR5(5:S) operant schedule that incorporates both a 5 min initial appetitive phase and a 25 min consummatory phase. We compared the drug-induced change in responding to that recorded following a reduction in motivational state induced by pre-feeding. In a second experiment we assessed the effects of SR141716A (0-3 mg/kg) on Pavlovian approach behaviour for a stimulus (lever) associated with food reward (CS+) and a neutral stimulus (lever) not associated with reward (CS-). RESULTS SR141716A reduced pellet consumption and instrumental responding during both the appetitive and consummatory phases of the second order schedule. Pre-feeding had a similar effect on responding during the appetitive phase, suggesting an effect on incentive motivation. SR141716A also blocked an enhancement of responding that occurred during the consummatory phase in pre-fed animals. SR141716A and pre-feeding had no effect on responding in the Pavlovian autoshaping paradigm. CONCLUSIONS SR141716A impacts on motivational processes in both the appetitive and consummatory phases of feeding behaviour.
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Affiliation(s)
- Zoë D Thornton-Jones
- Department of Psychology, John Maynard-Smith Building, University of Sussex, Brighton, Sussex, BN1 9QG, UK
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158
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Liu YL, Connoley IP, Wilson CA, Stock MJ. Effects of the cannabinoid CB1 receptor antagonist SR141716 on oxygen consumption and soleus muscle glucose uptake in Lep(ob)/Lep(ob) mice. Int J Obes (Lond) 2005; 29:183-7. [PMID: 15558076 DOI: 10.1038/sj.ijo.0802847] [Citation(s) in RCA: 239] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To investigate the effect of SR141716, a selective CB1 receptor antagonist, on energy expenditure and on glucose uptake in isolated soleus muscle of Lep(ob)/Lep(ob) mice. DESIGN Female Lep(ob)/Lep(ob) mice (8-10 weeks old) were treated with SR141716 (10 mg/kg, i.p. once daily) or vehicle for 7 days. MEASUREMENTS Oxygen consumption, daily food and water intake, body weight and glucose uptake in isolated soleus muscle. RESULTS SR141716 (10 mg/kg, i.p. once daily) resulted in a significant reduction of daily food intake (P<0.01) and body weight (P<0.05) 5 days after daily treatment. Body weight continued to be lower for the rest of the treatment period (P<0.05). There was no significant difference in body weight between the pair-fed and vehicle-treated animals. A 7-day treatment with SR141716 (10 mg/kg, i.p. once daily) caused 37% increase in basal oxygen consumption compared to that of vehicle-treated (90 min mean; P<0.01), and a significant 68% increase in glucose uptake in isolated soleus muscle preparations. CONCLUSION It is concluded that SR141716 has a direct effect on energy expenditure suggesting that the antiobesity effect of SR141716 is due to activation of thermogenesis in addition to the initial hypophagia. The increase in soleus muscle glucose uptake with SR141716 treatment may contribute to the improved glycaemia seen in the previous studies.
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Affiliation(s)
- Y L Liu
- Department of Physiology, Basic Medical Sciences, St George's Hospital Medical School, Tooting, London SW17 0RE, UK.
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159
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Poirier B, Bidouard JP, Cadrouvele C, Marniquet X, Staels B, O'Connor SE, Janiak P, Herbert JM. The anti-obesity effect of rimonabant is associated with an improved serum lipid profile. Diabetes Obes Metab 2005; 7:65-72. [PMID: 15642077 DOI: 10.1111/j.1463-1326.2004.00374.x] [Citation(s) in RCA: 148] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
We investigated the effects of chronic treatment with the CB1 receptor antagonist rimonabant (10 mg/kg/day p.o. for 10 weeks) in mice with established obesity (5-month high-fat diet). Untreated obese mice showed a weight gain of 46% (45.0 +/- 0.6 g vs. 30.8 +/- 0.5 g) compared with age-matched animals fed a standard diet. Rimonabant treatment, commencing after 5-month high-fat diet, produced a marked and sustained decrease in body weight (34.5 +/- 0.8 g vs. 47.2 +/- 0.5 g in the high-fat vehicle group, p < 0.001). The anti-obesity effect of rimonabant was similar to that obtained by switching obese mice from high-fat diet to standard laboratory diet during 10 weeks (final weight 33.7 +/- 0.6 g) and was associated with only transient (14 days) reduction in energy intake. Serum leptin, insulin and glucose levels were markedly elevated in obese animals. Rimonabant treatment significantly reduced these elevations (leptin -81%, insulin -78%, glucose -67%, p < 0.001 in all cases vs. high-fat vehicle group). In addition, rimonabant treatment modestly but significantly increased serum adiponectin levels (+18%, p < 0.05 vs. high-fat vehicle group). Obese mice demonstrated abnormal serum lipid profiles. Although rimonabant did not modify high-density lipoprotein cholesterol (HDLc) and had modest effects on total cholesterol, it significantly reduced triglycerides and low-density lipoprotein cholesterol (LDLc) and, notably, increased the HDLc/LDLc ratio (12.4 +/- 0.8 vs. 7.9 +/- 0.2 in high-fat vehicle group, p < 0.001). Therefore, in a model of established obesity, chronic rimonabant treatment produces a marked and sustained decrease in body weight (equivalent to that achieved by dietary change) which is associated with favourable modifications in serum biochemical and lipid profiles.
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Affiliation(s)
- B Poirier
- Cardiovascular-Thrombosis Department, Sanofi-Synthélabo Research, 91835 Chilly-Mazarin Cedex, France.
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160
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Osei-Hyiaman D, Depetrillo M, Harvey-White J, Bannon AW, Cravatt BF, Kuhar MJ, Mackie K, Palkovits M, Kunos G. Cocaine- and amphetamine-related transcript is involved in the orexigenic effect of endogenous anandamide. Neuroendocrinology 2005; 81:273-82. [PMID: 16131814 DOI: 10.1159/000087925] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2005] [Accepted: 07/03/2005] [Indexed: 01/01/2023]
Abstract
Endocannabinoids acting at CB1 cannabinoid receptors (CB1) increase appetite. In view of the predominant presynaptic localization of CB1 in the brain, we tested the hypothesis that the orexigenic effect of endocannabinoids involves inhibition of the release of a tonically active anorexigenic mediator, such as the peptide product of the cocaine- and amphetamine-related transcript (CART). The CB1 antagonist rimonabant inhibited food intake in food-restricted wild-type mice, but not in their CART-deficient littermates. Mice deficient in fatty acid amide hydrolase (FAAH), the enzyme responsible for the in vivo metabolism of the endocannabinoid anandamide, have reduced levels of CART-immunoreactive nerve fibers and terminals in several brain regions implicated in appetite control, including the arcuate, dorsomedial and periventricular nuclei of the hypothalamus, the amygdala, the bed nucleus of the stria terminalis and the nucleus accumbens, and treatment of FAAH(-/-) mice with rimonabant, 3 mg/kg/day for 7 days, increased CART levels toward those seen in FAAH(+/+) wild-type controls. In contrast, no difference in the density of CART-immunoreactive fibers was observed in the median eminence and the paraventricular nucleus of FAAH(+/+) and FAAH(-/-) mice. Acute treatment of wild-type mice with the cannabinoid agonist HU-210 resulted in elevated CART levels in the dorsomedial nucleus and the shell portion of the nucleus accumbens. These observations are compatible with CART being a downstream mediator of the CB1-mediated orexigenic effect of endogenous anandamide.
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Affiliation(s)
- Douglas Osei-Hyiaman
- Section on Neuroendocrinology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
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161
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Bradbury MJ, Campbell U, Giracello D, Chapman D, King C, Tehrani L, Cosford NDP, Anderson J, Varney MA, Strack AM. Metabotropic glutamate receptor mGlu5 is a mediator of appetite and energy balance in rats and mice. J Pharmacol Exp Ther 2004; 313:395-402. [PMID: 15590770 DOI: 10.1124/jpet.104.076406] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The metabotropic glutamate receptor subtype mGlu5 modulates central reward pathways. Many transmitter systems within reward pathways affect feeding. We examined the potential role of mGlu5 in body weight regulation using genetic and pharmacological approaches. Adult mice lacking mGlu5, mGluR5-/-, weighed significantly less than littermate controls (mGluR5+/+, despite no difference in ad libitum food intake. After overnight food deprivation, mGluR5-/- mice ate significantly less than their mGluR5+/+ controls when refeeding. When on a high fat diet, mGluR5-/- mice weighed less and had decreased plasma insulin and leptin concentrations. The selective mGlu5 antagonist MTEP [3-[(2-methyl-1,3-thiazol-4-yl)-ethynyl]-pyridine; 15 mg/kg s.c.] reduced refeeding after overnight food deprivation in mGluR5+/+, but not mGluR5-/- mice, demonstrating that feeding suppression is mediated via a mGlu5 mechanism. MTEP (1-10 mg/kg) decreased night-time food intake in rats in a dose-related manner. At 10 mg/kg, MTEP injected at 8.5, 4.5, or 0.5 h before refeeding reduced overnight food intake by approximately approximately 30%. Diet-induced obese (DIO) and age-matched lean rats were treated for 12 days with MTEP (3 or 10 mg/kg/day s.c.), dexfenfluramine (3 mg/kg/day s.c.), or vehicle. Daily and cumulative food intakes were reduced in DIO rats by MTEP and dexfenfluramine. Weight gain was prevented with MTEP (3 mg/kg), and weight and adiposity loss was seen with MTEP (10 mg/kg) and dexfenfluramine. Caloric efficiency was decreased, suggesting increased energy expenditure. In lean rats, similar, although smaller, effects were observed. In conclusion, using genetic and pharmacological approaches, we have shown that mGlu5 modulates food intake and energy balance in rodents.
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Affiliation(s)
- Margaret J Bradbury
- Department of Pharmacology, RY80Y-145, Merck Research Labs, Box 2000, Rahway, NJ 07065, USA
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162
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Pertwee RG. Inverse agonism and neutral antagonism at cannabinoid CB1 receptors. Life Sci 2004; 76:1307-24. [PMID: 15670612 DOI: 10.1016/j.lfs.2004.10.025] [Citation(s) in RCA: 341] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2004] [Accepted: 10/22/2004] [Indexed: 11/15/2022]
Abstract
There are at least two types of cannabinoid receptor, CB1 and CB2, both G protein coupled. CB1 receptors are expressed predominantly at nerve terminals and mediate inhibition of transmitter release whereas CB2 receptors are found mainly on immune cells, one of their roles being to modulate cytokine release. Endogenous cannabinoid receptor agonists also exist and these "endocannabinoids" together with their receptors constitute the "endocannabinoid system". These discoveries were followed by the development of a number of CB1- and CB2-selective antagonists that in some CB1 or CB2 receptor-containing systems also produce "inverse cannabimimetic effects", effects opposite in direction from those produced by cannabinoid receptor agonists. This review focuses on the CB1-selective antagonists, SR141716A, AM251, AM281 and LY320135, and discusses possible mechanisms by which these ligands produce their inverse effects: (1) competitive surmountable antagonism at CB1 receptors of endogenously released endocannabinoids, (2) inverse agonism resulting from negative, possibly allosteric, modulation of the constitutive activity of CB1 receptors in which CB1 receptors are shifted from a constitutively active "on" state to one or more constitutively inactive "off" states and (3) CB1 receptor-independent mechanisms, for example antagonism of endogenously released adenosine at A1 receptors. Recently developed neutral competitive CB1 receptor antagonists, which are expected to produce inverse effects through antagonism of endogenously released endocannabinoids but not by modulating CB1 receptor constitutive activity, are also discussed. So too are possible clinical consequences of the production of inverse cannabimimetic effects, there being convincing evidence that released endocannabinoids can have "autoprotective" roles.
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Affiliation(s)
- Roger G Pertwee
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, Scotland, UK.
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163
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Järbe TUC, Harris MY, Li C, Liu Q, Makriyannis A. Discriminative stimulus effects in rats of SR-141716 (rimonabant), a cannabinoid CB1 receptor antagonist. Psychopharmacology (Berl) 2004; 177:35-45. [PMID: 15167981 DOI: 10.1007/s00213-004-1916-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2003] [Accepted: 03/27/2004] [Indexed: 10/26/2022]
Abstract
OBJECTIVE To examine the discriminative stimulus effects of (i) the cannabinoid CB(1) receptor antagonist SR-141716 (SR, 5.6 mg/kg) and vehicle, and (ii) the cannabinoid receptor agonist Delta(9)-THC (THC, 1.8 mg/kg) and vehicle using a discriminated taste aversion (DTA) procedure. METHODS Two groups of rats ( n=6) were trained to discriminate between these drugs and vehicle in DTA ( t'=20 min). The 30-min drinking bout of tap water following drug (SR or THC) treatment was followed by an injection of lithium chloride (LiCl, 120 mg/kg) in the experimental animals. When offered water after vehicle pretreatment, experimental animals subsequently were given IP saline (NaCl, 10 ml/kg). Post-drinking treatment for controls ( n=6) was NaCl, irrespective of the pretreatment condition (SR, THC or vehicle). Additional water was provided during the afternoon (30 min) with no other manipulations. Food was available ad lib at all times. When the discriminations were established other doses and drugs were examined ( t'=20 min). In testing there were no post-drinking treatments. RESULTS The SR-related analog AM-251 (dose range: 1-5.6 mg/kg) substituted for SR, whereas other drugs such as the cannabinoid CB(2) receptor antagonist SR-144528 (3 and 10 mg/kg), THC (1-10 mg/kg), flumazenil (1-10 mg/kg), naloxone (1-10 mg/kg), morphine (10 and 18 mg/kg) and d-amphetamine (1 and 3 mg/kg) did not. There was a dose-related attenuation of SR-induced suppression of drinking when THC (1.8-10 mg/kg) was given together with SR (5.6 mg/kg). In the THC trained rats, SR (1-10 mg/kg), morphine (10 and 18 mg/kg) and d-amphetamine (1 and 3 mg/kg) did not substitute for THC. SR (1 mg/kg) attenuated the THC (1.8 mg/kg) induced suppression of drinking. Together with 3 mg/kg SR and 1.8 mg/kg THC, drinking was roughly equally suppressed in both the experimental group and the controls. CONCLUSION SR-141716 induces a discriminative stimulus complex in DTA that shows potential for further examination of cannabinoid receptor antagonism.
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Affiliation(s)
- Torbjörn U C Järbe
- Department of Psychology, Temple University, 265-67 Weiss Hall, 1701 North 13th Street, Philadelphia, PA 19122, USA.
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164
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Abstract
This review analyses the therapeutic usefulness of Delta(9)-tetrahydrocannabinol and its potential to induce adverse reactions on humans. During the last 30 years an enormous amount of research was carried out resulting in the disclosure of the cannabinoid system in Central Nervous System, with its CB(1) and CB(2) receptors, and the agonist anandamide. Under the clinical point of view, Delta(9)-THC produces some therapeutic benefits which are beyond reasonable doubt. Thus, the effects on nausea/emesis due to cancer chemotherapy, as appetite promoter, on some painful conditions and on symptoms of multiple sclerosis are clearly demonstrated. Delta(9)-THC is not devoid of ill effects. On the cognitive domain it impairs the human capacity to discriminate time intervals and space distances, vigilance, memory and the performance for mental work. On the psychic area Delta(9)-THC may induce unpleasant reactions such as disconnected thoughts, panic reactions, disturbing changes in perception, delusions and hallucinatory experiences. However, the long term effects on the psyche and cognition are not known as there are no reports of prolonged use of Delta(9)-THC. Actually, it has been proposed by WHO that Delta(9)-THC should be rescheduled to schedule IV of the United Nations Convention on Psychotropic Drugs, as it does not constitute a substantial risk to public health and its abuse is rare if at all.
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Affiliation(s)
- E A Carlini
- Department of Psychobiology, Federal University of São Paulo, Paulista School of Medicine, Rua Botucatu, 862-1 andar-Ed. Ciências Biomédicas 04023-062-São Paulo-SP, Brazil.
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165
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Ravinet Trillou C, Delgorge C, Menet C, Arnone M, Soubrié P. CB1 cannabinoid receptor knockout in mice leads to leanness, resistance to diet-induced obesity and enhanced leptin sensitivity. Int J Obes (Lond) 2004; 28:640-8. [PMID: 14770190 DOI: 10.1038/sj.ijo.0802583] [Citation(s) in RCA: 437] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE There is growing evidence for an implication of the CB1 receptor subtype of the endocannabinoid system in the regulation of eating and fat deposition. To further define the physiological role of these receptors in the control of energy balance, we characterized the phenotype of CB1 receptor knockout (CB1(-/-)) mice maintained on an obesity-prone regimen or on a standard chow. DESIGN CB1(-/-) male mice were compared to wild-type animals (CB1(+/+) male mice) in two feeding paradigms: (1) with a standard laboratory regimen (3.5 kcal/g, 14.5% of energy as fat) and (2) on a free-choice paradigm consisting of offering both the standard laboratory chow and a high-fat diet (HFD) (4.9 kcal/g, 49% of energy as fat). RESULTS When maintained on the standard diet, CB1(-/-) mice are lean. At the age of 20 weeks, their body weight and adiposity are, respectively, 24 and 60% lower than that of CB1(+/+) mice. They are slightly hypophagic, but when expressed as percent of body weight, their relative energy intake is similar to that of the wild-type animals. Furthermore, inactivation of CB1 receptors reduces plasma insulin and leptin levels, and enhances the response to intracerebroventricular leptin injection. The free-choice paradigm shows that the preference for a high-fat highly palatable chow is slightly delayed in onset but maintained in CB1(-/-) mice. However, loading CB1(-/-) mice with this obesity-prone diet does not result in development of obesity. Knockout mice do not display hyperphagia or reduction of their relative energy intake in contrast to CB1(+/+) mice, and their feeding efficiency remains low. These data suggest an improved energetic metabolism with the high-fat regimen. Furthermore, the insulin resistance normally occurring in HFD-fed mice is not present in CB1(-/-) mice. CONCLUSION These results provide evidence that the stimulation of CB1 receptors is a key component in the development of diet-induced obesity, and that these receptors and their endogenous ligands are implicated not only in feeding control but also in peripheral metabolic regulations. The lack of effect of SR141716, a selective CB1 receptor antagonist, in CB1(-/-) mice further supports this hypothesis, as this compound was previously shown to display potent anti-obesity properties in diet-induced obese C57BL/6 mice.
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Affiliation(s)
- C Ravinet Trillou
- Central Nervous System Research, Sanofi-Synthélabo, Toulouse Cedex, France.
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166
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Carai MAM, Colombo G, Gessa GL. Rapid tolerance to the intestinal prokinetic effect of cannabinoid CB1 receptor antagonist, SR 141716 (Rimonabant). Eur J Pharmacol 2004; 494:221-4. [PMID: 15212978 DOI: 10.1016/j.ejphar.2004.05.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2004] [Revised: 04/28/2004] [Accepted: 05/10/2004] [Indexed: 11/17/2022]
Abstract
The cannabinoid CB(1) receptor antagonist, SR 141716 (Rimonabant), has been reported to stimulate, when acutely administered, intestinal motility in mice. The present study was aimed at determining whether tolerance develops to its repeated administration. Mice were treated twice a day for up to 8 consecutive days with 0, 3 and 5.6 mg/kg SR 141716 (i.p.). On days 1, 3, 5 and 8, separate groups of mice were treated intragastrically with a non-absorbable colored marker (carmine). The distance traveled by the head of the marker in the small intestine was recorded. On day 1, SR 141716 markedly activated intestinal peristalsis, but complete tolerance to this effect developed within the third day of treatment. The results may have some relevance to the proposed future clinical use of SR 141716.
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Affiliation(s)
- Mauro A M Carai
- Bernard B. Brodie Department of Neuroscience, University of Cagliari, Viale Diaz 182, I-09126 Cagliari, Italy.
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167
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Chen RZ, Huang RRC, Shen CP, MacNeil DJ, Fong TM. Synergistic effects of cannabinoid inverse agonist AM251 and opioid antagonist nalmefene on food intake in mice. Brain Res 2004; 999:227-30. [PMID: 14759503 DOI: 10.1016/j.brainres.2003.12.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/12/2003] [Indexed: 11/28/2022]
Abstract
Oral administration of the opioid antagonist nalmefene alone (up to 20 mg/kg) failed to show a significant effect on acute food intake in mice. However, combined oral dosing of nalmefene and subthreshold doses of AM251, a cannabinoid CB1 receptor inverse agonist, led to a significant reduction in food intake in both lean and diet-induced obese (DIO) mice. Furthermore, the anorectic effect of a high dose of AM251 was further enhanced when co-administered with nalmefene. The results support a synergistic interaction between opioid and cannabinoid systems in regulating feeding behavior.
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Affiliation(s)
- Richard Z Chen
- Department of Metabolic Disorders, PO Box 2000, RY80M-213, Rahway, NJ 07065, USA.
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168
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Zhou D, Shearman LP. Voluntary exercise augments acute effects of CB1-receptor inverse agonist on body weight loss in obese and lean mice. Pharmacol Biochem Behav 2004; 77:117-25. [PMID: 14724049 DOI: 10.1016/j.pbb.2003.10.015] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cannabinoid CB1 receptor (CB1R) inverse agonists reduce appetite and body weight (BW) gain in various species. Exercise is thought to be a natural reward process and the cannabinoid system is also believed to influence reward. We tested the hypothesis that voluntary exercise would augment the effects of AM251, a CB1R inverse agonist, on food intake (FI) and BW loss in murine genetic models of obesity. ob/ob, agouti yellow (A(y)), and lean C57BL/6J mice were treated via oral gavage with vehicle or AM251 (1, 3, or 10 mg/kg) 1 h before the dark cycle. The suppressive effects of 3 and 10 mg/kg AM251 on overnight FI, BW gain, and water intake (WI) were significant in ob/ob mice. In contrast, in A(y) mice, 10 mg/kg AM251 decreased FI and BW gain while it did not influence WI. Food consumption of ob/ob and A(y) mice, as evidenced by feeding frequency (FF) and feeding duration (FD), was reduced by AM251 for 4-6 h. AM251 at these doses had no impact on the appetitive behavior or BW gain of lean mice. After a 1-week wash-out period, mice were given running wheels in their home cages. With running wheel exercise, lean and obese mice exhibited increased sensitivity to AM251. Low voluntary wheel running activity of ob/ob mice precluded detection of combined effects of AM251 and exercise in this genetic model of obesity. Lean and agouti mice given AM251 combined with exercise lost a greater amount of BW than with AM251 alone. Our data suggest that voluntary exercise can enhance CB1R inverse agonist effects on appetite and BW loss in both lean and agouti obese mice.
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MESH Headings
- Animals
- Body Weight/drug effects
- Body Weight/physiology
- Dose-Response Relationship, Drug
- Eating/drug effects
- Eating/physiology
- Female
- Mice
- Mice, Inbred C57BL
- Mice, Obese
- Physical Conditioning, Animal/physiology
- Piperidines/pharmacology
- Piperidines/therapeutic use
- Pyrazoles/pharmacology
- Pyrazoles/therapeutic use
- Receptor, Cannabinoid, CB1/agonists
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Receptor, Cannabinoid, CB1/physiology
- Thinness/physiopathology
- Weight Loss/drug effects
- Weight Loss/physiology
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Affiliation(s)
- Dan Zhou
- Department of Pharmacology, Merck Research Laboratories, RY80Y-150, 126 E. Lincoln Avenue, Rahway, NJ 07065, USA
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169
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Abstract
Obesity has been described as a global epidemic. Its increasing prevalence is matched by growing costs, not only to the health of the individual, but also to the medical services required to treat a range of obesity-related diseases. In most instances, obesity is a product of progressively less energetic lifestyles and the over-consumption of readily available, palatable, and highly caloric foods. Past decades have seen massive investment in the search for effective anti-obesity therapies, so far with limited success. An important part of the process of developing new pharmacologic treatments for obesity lies in improving our understanding of the psychologic and physiologic processes that govern appetite and bodyweight regulation. Recent discoveries concerning the endogenous cannabinoids are beginning to give greater insight into these processes. Current research indicates that endocannabinoids may be key to the appetitive and consummatory aspects of eating motivation, possibly mediating the craving for and enjoyment of the most desired, most fattening foods. Additionally, endocannabinoids appear to modulate central and peripheral processes associated with fat and glucose metabolism. Selective cannabinoid receptor antagonists have been shown to suppress the motivation to eat, and preferentially reduce the consumption of palatable, energy-dense foods. Additionally, these agents act to reduce adiposity through metabolic mechanisms that are independent of changes in food intake. Given the current state of evidence, we conclude that the endocannabinoids represent an exciting target for new anti-obesity therapies.
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Affiliation(s)
- Tim C Kirkham
- School of Psychology, The University of Liverpool, Liverpool L69 7ZA, UK.
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