Ipsilateral turning behavior induced by unilateral microinjections of a cannabinoid into the rat subthalamic nucleus

The subthalamic nucleus contains cannabinoid receptors and cannabinoid receptor mRNA. However, the role of cannabinoid receptors in this nucleus has not been examined. In order to investigate the functional role of cannabinoid receptors in the rat subthalamic nucleus, turning activity was observed following unilateral microinjection of the synthetic cannabinoid CP 55,940. CP 55,940 (10 μg) induced ipsilateral turning. This effect was blocked by coadministration of the cannabinoid receptor antagonist SR141716A (5 μg). These results suggest that cannabinoid receptors in the subthalamic nucleus mediate an inhibition of motor activity.