Effect of chronic exposure to rimonabant and phytocannabinoids on anxiety-like behavior and saccharin palatability.

Lesley D O'Brien, Kiri L Wills, Blair Segsworth, Brittany Dashney, Erin M Rock, Cheryl L Limebeer, Linda A Parker

Department of Psychology and Collaborative Neuroscience Program, University of Guelph, Guelph, ON, Canada N1G 2W1.

Pharmacology, biochemistry, and behavior 2013 Jan

filter terms:

The acute effects of cannabinoid compounds have been investigated in animal models of anxiety-like behavior and palatability processing. However, the chronic effects of cannabinoids in such models are poorly understood. Experiment 1 compared the effects of both acute and chronic (14 days) exposure to the CB(1) receptor inverse agonist/antagonist, rimonabant, and the cannabis-derived CB(1) receptor neutral antagonist, tetrahydrocannabivarin (THCV), on: 1) time spent in the open, lit box in the Light-Dark (LD) immersion model of anxiety-like behavior and 2) saccharin hedonic reactions in the taste reactivity (TR) test of palatability processing. Experiment 2 compared the effects of chronic administration of cannabis-derived Δ(9)-tetrahydrocannabinol (Δ(9)-THC), cannabidiol (CBD) and cannabigerol (CBG) in these models. Tests were administered on Days 1, 7 and 14 of drug administration. In Experiment 1, rimonabant, but not THCV, produced an anxiogenic-like reaction in the LD immersion test and reduced saccharin palatability in the TR test; both of these effects occurred acutely and were not enhanced by chronic exposure. In Experiment 2, Δ(9)-THC also produced an acute anxiogenic-like reaction in the LD immersion test, without enhancement by chronic exposure. However, Δ(9)-THC enhanced saccharin palatability in the TR test on Day 1 of drug exposure only. CBD and CBG did not modify anxiety-like responding, but CBG produced a weak enhancement of saccharin palatability on Day 1 only. The results suggest that the anxiogenic-like reactions and the suppression of hedonic responding produced by rimonabant, are mediated by inverse agonism of the CB(1) receptor and these effects are not enhanced with chronic exposure. Copyright © 2012 Elsevier Inc. All rights reserved.

Citation

Lesley D O'Brien, Kiri L Wills, Blair Segsworth, Brittany Dashney, Erin M Rock, Cheryl L Limebeer, Linda A Parker. Effect of chronic exposure to rimonabant and phytocannabinoids on anxiety-like behavior and saccharin palatability. Pharmacology, biochemistry, and behavior. 2013 Jan;103(3):597-602