Differential response of striatal dopamine and muscarinic cholinergic receptor subtypes to the loss of dopamine. III. Results in Parkinson's disease cases.

The distribution and number of DA uptake sites, DA receptors (D1 and D2) and cholinergic muscarinic receptors (M1 and M2) were examined by autoradiography in the striatal complex of Parkinson's and age-matched control cases. The greatest loss of DA uptake sites occurred in the dorsolateral striatum which was the only region showing an increase in D2 receptors. The number of M2 receptors was reduced in the dorsolateral striatum and M1 receptors were reduced in most regions of the striatum. The anatomical pattern of changes in DA uptake sites, D2 receptors and M2 receptors suggests a coordinated change in the dopaminergic-cholinergic interneuron synapse in Parkinson's disease.