Excitatory effect of iontophoretically applied dopamine on identified neurons of the rat subthalamic nucleus.

The effects of iontophoretic applications of dopamine were studied on neurons of the subthalamic nucleus (STN) identified by their histological location, their response to contralateral vibrissae stimulation and, for 33% of them, by their antidromic activation from the globus pallidus. A potent and consistent excitatory effect of dopamine was found for all the STN neurons tested. Depression of spontaneous activity or mixed responses were never recorded in the STN. The excitatory response was antagonized by iontophoretic application of flupenthixol.