Psychopharmacology (1998) 135 : 324–332

© Springer-Verlag 1998

ORIGINAL INVESTIGATION

Frederique Chaperon · Philippe Soubrie Alain J. Puech · Marie-Helene Thiebot

Involvement of central cannabinoid (CB1) receptors in the establishment of place conditioning in rats

Received: 14 March 1997 / Final version: 28 July 1997

Abstract The involvement of cannabinoid processes in positive reinforcement was studied using an unbiased, one-compartment, conditioned place preference (CPP) procedure in rats. This was achieved by examining the ability of the selective antagonist of the CB1 cannabinoid receptor subtype, SR 141716, to counteract the CPP supported by classical reinforcers. The acquisition of CPP induced by cocaine (2 mg/kg), morphine (4 mg/kg) and food (standard chow and sucrose pellets) was dose-dependently blocked by pre-pairing administration of SR 141716 (0.03–3 mg/kg). However, SR 141716 (up to 10 mg/kg) did not significantly counteract the expression of cocaineinduced CPP. On the other hand, the synthetic CB receptor agonist, WIN 55212-2 (0.3–1 mg/kg), established a robust place aversion (CPA), as already described with other agonists, and CPP was never observed, even at 100-fold lower doses. The aversive effect of WIN 55212-2 was reversed by SR 141716 (0.3–1 mg/kg), suggesting that it was accounted for by the stimulation of CB1 receptors. These findings indicate that, on their own, CB receptor agonists are unable to generate the processes necessary to induce a pleasurable state in animals, as assessed in place conditioning procedures. Nevertheless, a cannabinoid link may be involved in the neurobiological events, allow

F. Chaperon · M.H. Thiebot (*)

INSERM U.288, Faculty of Medicine Pitie-Salpetriere, 91 bd de l’Hopital,

F-75634 Paris Cedex 13, France

Fax (+33) 140779596,