Activation of the cannabinoid receptor by delta 9-tetrahydrocannabinol reduces gamma-aminobutyric acid uptake in the globus pallidus.

The interaction between GABA (gamma-aminobutyric acid) and cannabinoids in the globus pallidus was investigated by evaluating the effects of delta 9-tetrahydrocannabinol on [3H]GABA uptake into slices of rat globus pallidus. delta 9-Tetrahydrocannabinol caused a concentration-dependent decrease in GABA uptake (51% decrease at 100 microM delta 9-tetrahydrocannabinol, IC50 = 18.95 microM). This effect was reversed in a concentration-dependent manner (IC50 = 11.9 microM) by the cannabinoid receptor antagonist SR 141716A (N-(piperidin-1-yl-)5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-me thyl-1 H-pyrazole-3-arboxiamidehydrochloride. SR 141716A alone did not affect GABA uptake. These results show that cannabinoid receptor activation reduces GABA uptake in the globus pallidus.