Cannabinoid influences on palatability: microstructural analysis of sucrose drinking after delta(9)-tetrahydrocannabinol, anandamide, 2-arachidonoyl glycerol and SR141716.
BACKGROUND
Central cannabinoid systems have been implicated in appetite control through the respective hyperphagic and anorectic actions of CB1 agonists and antagonists. The motivational changes underlying these actions remain to be determined, but may involve alterations to food palatability.


OBJECTIVE
The mode of action of cannabinoids on ingestion was investigated by examining the effects of exogenous and endogenous agonists, and a selective CB1 receptor antagonist, on licking microstructure in rats ingesting a palatable sucrose solution.


METHODS
Microstructural analyses of licking for a 10% sucrose solution was performed over a range of agonist and antagonist doses administered to non-deprived, male Lister hooded rats.


RESULTS
Delta(9)-tetrahydrocannabinol (0.5, 1 and 3 mg/kg) and anandamide (1 mg/kg and 3 mg/kg) significantly increased total number of licks. This was primarily due to an increase in bout duration rather than bout number. There was a non-significant increase in total licks following administration of 2-arachidonoyl glycerol (0.2, 1.0 and 2.0 mg/kg), whereas administration of the CB1 antagonist SR141716 (1 mg/kg and 3 mg/kg) significantly decreased total licks. All drugs, with the exception of anandamide, significantly decreased the intra-bout lick rate. An exponential function fitted to the cumulative lick rate curves for each drug revealed that all compounds altered the asymptote of this function without having any marked effects on the exponent.


CONCLUSIONS
These data are consistent with endocannabinoid involvement in the mediation of food palatability.
Higgs
Suzanne
S
School of Psychology, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK. s.higgs.1@bham.ac.uk
Williams
Claire M
CM
Kirkham
Tim C
TC
D000818:Animals; D019167:Appetite Stimulants; D001095:Arachidonic Acids / Q000494:pharmacology; D001522:Behavior, Animal / Q000187:drug effects; D063385:Cannabinoid Receptor Modulators; D002186:Cannabinoids / Q000819:agonists / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004327:Drinking Behavior / Q000187:drug effects*; D013759:Dronabinol / Q000494:pharmacology; D063388:Endocannabinoids; D005989:Glycerides / Q000494:pharmacology; D008297:Male; D018377:Neurotransmitter Agents / Q000494:pharmacology; 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; D013395:Sucrose; D013997:Time Factors
D019167:Appetite Stimulants; D001095:Arachidonic Acids; D063385:Cannabinoid Receptor Modulators; D002186:Cannabinoids; D063388:Endocannabinoids; D005989:Glycerides; D018377:Neurotransmitter Agents; D010880:Piperidines; D053284:Polyunsaturated Alkamides; D011720:Pyrazoles; D043882:Receptors, Cannabinoid; D011955:Receptors, Drug; D013395:Sucrose; D013759:Dronabinol; C094503:glyceryl 2-arachidonate; D000077285:Rimonabant; C078814:anandamide