DELTA-9-TETRAHYDROCANNABINOL AND ANANDAMIDE ENHANCE THE ABILITY OF MUSCIMOL TO INDUCE CATALEPSY IN THE GLOBUS-PALLIDUS OF RATS

Doses of 3 or 30 mug of DELTA9-tetrahydrocannabinol markedly increased the ability of 25 ng of muscimol to delay the descent of rats from a horizontal bar (descent latency) when these drugs were coadministered bilaterally into the globus pallidus. Intrapallidal injections of 30 m ug of the putative endogenous cannabinoid, anandamide, also increased the effect of muscimol on descent latency. These data indicate that th e production of catalepsy by cannabinoids may depend at toast in part on an ability to enhance GABAergic transmission in the globus pallidus and support the hypothesis that anandamide is indeed an endogenous li gand for the cannabinoid receptor.