The influence of pallidal deep brain stimulation on striatal dopaminergic metabolism in the rat

Deep brain stimulation of the globus pallidus internus has been recently sh own to alleviate parkinsonian symptoms and levodopa-induced dyskinesias, Ho wever, its exact mechanisms of action are unclear. Pallidal neurones are co nnected via various pathways to the dopaminergic nigrostriatal system. In t he present study we investigated the hypothesis that deep brain stimulation of the entopeduncular nucleus (corresponds to the human internal pallidum) affects striatal dopaminergic metabolism in naive and 6-hydroxydopamine (6 -OHDA) lesioned rats using microdialysis. Our results show that stimulation of the entopeduncular nucleus does not significantly affect striatal dopam ine metabolism (of dopamine, 3,4-dihdroxyphenylacetic acid and homovanillic acid) in naive and 6-OHDA-lesioned animals. They contrast with our previou s observations that deep brain stimulation of the subthalamic nucleus incre ases striatal dopamine metabolism suggesting differential effects of these nuclei on striatal dopamine metabolism. (C) 2000 Elsevier Science Ireland L td. All rights reserved.