Anandamide induces overeating: mediation by central cannabinoid (CB1) receptors.
BACKGROUND
Central cannabinoid systems have been implicated in appetite regulation by the respective hyperphagic actions of exogenous cannabinoids, such as delta9-THC, and hypophagic effects of selective cannabinoid receptor antagonists.


OBJECTIVE
This study examined whether an endogenous cannabinoid, anandamide, could induce overeating, via a specific action at central (CB1) cannabinoid receptors.


METHODS
Pre-satiated male rats (n=18), received subcutaneous injections of anandamide (0.5, 1.0, 5.0, 10.0 mg/kg) before 3-h, nocturnal food intake tests. In a second series of intake tests (n=8), anandamide injection (1.0 mg/kg) was preceded by injection of the specific CB1 receptor antagonist, SR141716 (0.1, 0.5, 1.0 mg/kg SC).


RESULTS
All doses of anandamide induced significant overeating, with 1.0 mg/kg being most potent. Additionally, hyperphagia induced by 1.0 mg/kg anandamide was dose-dependently attenuated by SR141716 pretreatment.


CONCLUSIONS
This first demonstration of anandamide-induced, CB -mediated, overeating provides important evidence for the involvement of a central cannabinoid system in the normal control of eating.
Williams
C M
CM
Department of Psychology, University of Reading, Whiteknights, UK.
Kirkham
T C
TC
D000818:Animals; D001095:Arachidonic Acids / Q000494:pharmacology* / Q000502:physiology; D002186:Cannabinoids / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D063388:Endocannabinoids; D006963:Hyperphagia / Q000503:physiopathology; D008297:Male; D010880:Piperidines / Q000494:pharmacology; D053284:Polyunsaturated Alkamides; D011720:Pyrazoles / Q000494:pharmacology; D051381:Rats; D043882:Receptors, Cannabinoid; D011955:Receptors, Drug / Q000037:antagonists & inhibitors / Q000187:drug effects*; D000077285:Rimonabant
D001095:Arachidonic Acids; D002186:Cannabinoids; D063388:Endocannabinoids; D010880:Piperidines; D053284:Polyunsaturated Alkamides; D011720:Pyrazoles; D043882:Receptors, Cannabinoid; D011955:Receptors, Drug; D000077285:Rimonabant; C078814:anandamide