D3 RECEPTOR EXPRESSION WITHIN THE BASAL GANGLIA IS NOT AFFECTED BY PARKINSONS-DISEASE

Quantitative receptor autoradiography and in situ hybridization were u sed to investigate the expression of dopamine D3 receptors in sections of human brain containing limbic (nucleus accumbens) and striatal (ca udate nucleus, putamen) regions. High levels of dopamine D3 receptor m RNA and specific H-3](+/-)7-hydroxy-N,N-di-N-propyl-2-aminotetralin ([ H-3]7-OH-DPAT) binding sites were detected in the nucleus accumbens wi th lower levels in the caudate nucleus and putamen. No difference in D 3 receptor expression was observed between normal and parkinsonian bra in. These results indicate that D3 receptor expression is not altered in Parkinson's disease. In addition, they suggest that dopamine releas e in striatal and limbic areas is not necessary for maintenance of D3 receptor expression.