Canna~Fangled Abstracts

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

By January 9, 2014No Comments
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Effect of chronic exposure to rimonabant and phytocannabinoids on anxiety-like behavior and saccharin palatability

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

Abstract

elsevierThe 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 CB1receptor inverse agonist/antagonist, rimonabant, and the cannabis-derived CB1 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 Δ9-tetrahydrocannabinol (Δ9-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, Δ9-THC also produced an acute anxiogenic-like reaction in the LD immersion test, without enhancement by chronic exposure. However, Δ9-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 CB1 receptor and these effects are not enhanced with chronic exposure.


Highlights

► Rimonabant, but not THCV, produced an anxiogenic-like response. ► Δ9-THC also produced an anxiogenic–like response. ► Rimonabant suppressed, but Δ9-THC enhanced, saccharin palatability. ► Chronic exposure did not enhance either behavior.

Keywords

  • Anxiety;
  • Depression;
  • Palatability;
  • Appetite;
  • Cannabinoid;
  • CB1;
  • Tetrahydrocannabivarin;
  • Cannabidiol;
  • Cannabigerol;
  • Rimonabant;
  • Delta-9-tetrahydrocannabinol

Figures and tables from this article:

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Fig. 1.

Mean (± sem) seconds in the lit open box in the LD immersion test of anxiety-like behavior among rats injected with 2.5 mg/kg SR141716, 2.5 mg/kg THCV or VEH on Days 1, 7 and 14 of chronic drug administration in Experiment 1.

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Fig. 2.

Mean (± sem) number of hedonic reactions in the TR test among rats injected with 2.5 mg/kg SR141716, 2.5 mg/kg THCV or VEH on Days 1, 7 and 14 of chronic drug administration in Experiment 1.

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Fig. 3.

Mean (± sem) seconds in the lit open box in the LD immersion test of anxiety-like behavior among rats injected with 2.5 mg/kg Δ9-THC, 2.5 mg/kg CBD, 2.5 mg/kg CBG or VEH on Days 1, 7 and 14 of chronic drug administration in Experiment 1.

Full-size image (13 K)
Fig. 4.

Mean (± sem) number of hedonic reactions in the TR test among rats injected with 2.5 mg/kg Δ9-THC, 2.5 mg/kg CBD, 2.5 mg/kg CBG or VEH on Days 1, 7 and 14 of chronic drug administration in Experiment 1.

Corresponding author contact information
Corresponding author at: Department of Psychology, University of Guelph, Guelph, Ontario, Canada N1G 2W1. Tel.: + 1 519 824 4120, 56330; fax: + 1 519 837 8629.
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Equally contributed.

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