EFFECTS OF INTRASTRIATAL CANNABINOIDS ON ROTATIONAL BEHAVIOR IN RATS - INTERACTIONS WITH THE DOPAMINERGIC SYSTEM

The effect of unilateral intrastriatal cannabinoid receptor stimulatio n on rotational behavior in rats was explored. The potent cannabinoid agonist CP 55,940 (5 mu g/0.05 mu l) induced contralateral turning whe n microinjected unilaterally into the striatum. The D-2 dopamine agoni st quinpirole reversed this contralateral rotation but failed to affec t motor behavior on its own. Finally, the D-1 dopamine agonist SKF 829 58 inhibited movement when administered. into the striatum and this in hibition was reversed by co-administration of the cannabinoid agonist. Surprisingly, microinjections of the cannabinoid agonist into the str iatum induced movement through activation of the striatonigral pathway and/or inhibition of the striatopallidal pathway, while the D-1 dopam ine agonist produced the opposite effect. Synapse 30:221-226, 1998. (C ) 1998 Wiley-Liss, Inc.