D-2 dopamine receptors in the frontal cortex of rat and human.
D-2 dopamine receptors and serotonin receptors in the frontal cortex of rat and human were labelled with 3H-spiroperidol. The D-2 receptors were then distinguished in 4 ways. Dissociation of spiroperidol was biphasic, indicating two populations of sites. Cinanserin in competition with 3H-spiroperidol exhibited high (75%) and low (25%) affinity sites. Dopamine and LY 141865 in competition with 1.25 nM 3H-spiroperidol exhibited high (20-25%) and low (80-75%) affinity sites in the absence of cinanserin, while in the presence of 300 nM cinanserin only the high affinity sites remained. Lesioning of the dopaminergic meso-cortical pathway increased the number of cinanserin-resistant sites by 26%. Thus 3H-spiroperidol binding in the presence of cinanserin can be used to selectively label D-2 receptors in the frontal cortex.
D000818:Animals; D001667:Binding, Competitive; D002540:Cerebral Cortex / Q000378:metabolism*; D002928:Cinanserin / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism; D004873:Ergolines / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008297:Male; D019257:Quinpirole; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000378:metabolism*; D013134:Spiperone / Q000378:metabolism
D004873:Ergolines; D011954:Receptors, Dopamine; D019257:Quinpirole; D013134:Spiperone; D002928:Cinanserin; D004298:Dopamine