6-Hydroxydopamine lesions reduce specific [3H]sulpiride binding in the rat substantia nigra: direct evidence for the existence of nigral D-2 autoreceptors.
[3H]Sulpiride bound to substantia nigra homogenates in a saturable manner and with a pharmacological profile typical of a specific D-2 ligand. Unilateral 6-OH-dopamine (DA) lesions of the nigrostriatal DA neurons reduced by 27-46% the Bmax of the specific [3H]sulpiride binding in substantia nigra homogenates depending on the time after 6-OHDA lesion and significantly increased the Bmax in the caudate. KDs remained unchanged in both areas. The localization of specific [3H]sulpiride binding and its reduction in the substantia nigra of the 6-OHDA-lesioned side were confirmed by quantitative autoradiography. The results provide evidence for the existence of D-2 autoreceptors in substantia nigra.
D000818:Animals; D001345:Autoradiography; D006892:Hydroxydopamines / Q000494:pharmacology*; D066298:In Vitro Techniques; D007202:Indicators and Reagents; D007700:Kinetics; D008297:Male; D008995:Monoamine Oxidase / Q000378:metabolism; D016627:Oxidopamine; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects / Q000378:metabolism*; D013378:Substantia Nigra / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D013469:Sulpiride / Q000378:metabolism*
D006892:Hydroxydopamines; D007202:Indicators and Reagents; D011954:Receptors, Dopamine; D013469:Sulpiride; D016627:Oxidopamine; D008995:Monoamine Oxidase