High frequency stimulation of the subthalamic nucleus increases the extracellular contents of striatal dopamine in normal and partially dopaminergic denervated rats

The subthalamic nucleus (STN) has come under focus in Parkinson disease (PD ) because of recent advances in the understanding of the functional organiz ation of the basal ganglia in normal and pathological conditions. Manipulat ions of the STN have been described to compensate for some imbalance in mot or output of the basal ganglia in animal models of PD and have been propose d as a potential therapeutic target in humans. indeed. high frequency stimu lation (HFS) (130 Hz) of the STN has beneficial effects in severe parkinson ian patients but the precise mechanisms underlying these clinical results r emain to be elucidated. To date, very little is known concerning the effect of HFS-STN on striatal dopaminergic transmission. Since it has been report ed that dopaminergic medication may be reduced in PD patients under HFS-STN , our goal was to study the effect of HFS-STN on striatal dopamine (DA) tra nsmission by using intracerebral microdialysis in normal and partially DA d enervated rats. Our results show that HFS-STN induces a significant increas e of extracellular DA in the striatum of nor mal and partially DA lesioned rats while striatal extracellular levels of DOPAC were not affected. we con clude that HFS-STN acts directly and/or indirectly on striatal DA levels in control or partially DA lesioned rats.