Effects of intrastriatal cannabinoids on rotational behavior in rats: Interactions with the dopaminergic system

The effect of unilateral intrastriatal cannabinoid receptor stimulation on rotational behavior in rats was explored. The potent cannabinoid agonist CP 55,940 (5 μg/0.5 μl) induced contralateral turning when microinjected unilaterally into the striatum. The D₂dopamine agonist quinpirole reversed this contralateral rotation but failed to affect motor behavior on its own. Finally, the D₁dopamine agonist SKF 82958 inhibited movement when administered into the striatum and this inhibition was reversed by co-administration of the cannabinoid agonist. Surprisingly, microinjections of the cannabinoid agonist into the striatum induced movement through activation of the striatonigral pathway and/or inhibition of the striatopallidal pathway, while the D₁dopamine agonist produced the opposite effect. Synapse 30:221–226, 1998. © 1998 Wiley-Liss, Inc.