A detailed anatomical analysis of neurotransmitter receptors in the putamen and caudate in Parkinson's disease and Alzheimer's disease.

Autoradiography allows precise anatomical matching as well as quantification of receptor density and is an ideal procedure to investigate neurotransmitter receptor distribution. Post mortem tissue from the caudate and putamen was investigated in cases of Parkinson's disease, Alzheimer's disease and age matched controls. Autoradiography was used to determine benzodiazepine, muscarinic cholinergic, D1 and D2 dopamine receptor density in these regions. This work shows that within the control group there is significantly higher benzodiazepine receptor density in the medial portion of the caudate and putamen when compared to lateral region. In the caudate nucleus there is a 15% (not significant) decrease of these receptors from rostral to caudal, no such decrease was present in the putamen. Muscarinic and both D1 and D2 dopamine receptors were evenly distributed in the control cases. Significant abnormalities in Parkinson's disease included loss of benzodiazepine receptors in the mid and caudal portions of the putamen and a decrease in muscarinic receptor density in the rostral putamen in Parkinson's disease.