SHORT REPORT: PDF OnlySR 141716A, a cannabinoid receptor antagonist, reverses the behavioural effects of anandamide-treated ratsCosta, B.; Vailati, S.; Colleoni, M. Author Information Institute of Pharmacology, Faculty of Sciences MM.FF.NN., University of Milan, via Vanvitelli, 32/A, 20129, Milan, Italy Correspondence to M. Colleoni, Institute of Pharmacology, Faculty of Sciences MM.FF.NN., University of Milan, via Vanvitelli 32/A, 20129, Milano, Italy. E-mail:[email protected] Received 10 September 1998; accepted 4 January 1999 Behavioural Pharmacology 10(3):p 327-331, May 1999. Buy Abstract We employed the CB1 cannabinoid receptor antagonist SR 141716A (3mg/kg, i.p.) to investigate whether behavioural effects induced in rats by anandamide, an endogenous cannabinoid (20 mg/kg, i.p.), were mediated by the cannabinoid CB1 receptor. Anandamide reduced ambulatory (67%) and non-ambulatory activities (rearing and grooming, 84% and 90% respectively), with a strong cataleptic effect, produced hypothermia (about -1°C) and hindlimb splaying, and reduced defecation (79%). It did not significantly increase either the tail-flick or hot-plate latencies. Except for the decreased defecation, these responses were all blocked by SR 141716A. Although only single doses of the agonist and antagonist were used, the findings indicate that these behavioural effects are probably mediated by an interaction with cannabinoid CB1 receptors. © 1999 Lippincott Williams & Wilkins, Inc.