Differential effects of endocannabinoids on [3H]-GABA uptake in the rat globus pallidus

In the globus pallidus, cannabinoid CB1 receptors are localized pre-synaptically on GABAergic neurons. We assessed the influence of the endocannabinoids, anandamide, 2-arachidonoyl-glycerol (2-AG) and noladin ether, on the uptake of [3H]-GABA in pallidal slices from rat. Both 2-AG and noladin ether increased [3H]-GABA uptake (by 40.8 ± 8.0% and 38.4 ± 12.5%). The effect of 2-AG was blocked by the cannabinoid CB1 receptor antagonist AM 251. In contrast, neither anandamide nor the agonist WIN 55,212-2 had an effect on [3H]-GABA uptake. Different roles might be played by different endocannabinoids, both physiologically and in basal ganglia disorders, such as Parkinson's disease.