Supersensitization of intrastriatal dopamine receptors involved in opposite regulation of acetylcholine release in Parkinson's model rats.

Using striatal microdialysis, we studied effects of SKF 38393, a D1 agonist, and quinpirole, a D2 agonist, on the acetylcholine (ACh) release from the striatum of 6-hydroxydopamine (6-OHDA)-lesioned rats by local infusion into the striatum. The present experiments clearly demonstrated evidence for the existence of intrastriatal D1 and D2 receptors regulating ACh release and for supersensitization of the striatal stimulatory D1 and inhibitory D2 receptor mechanisms in 6-OHDA lesioned rats.