CNS distribution of D1 receptors: use of a new specific D1 receptor antagonist, [3H]SCH39166.
D1 dopamine receptors have been localized using a radioactive form of a new specific antagonist, [3H]SCH39166. This compound has been shown, in in vitro binding studies, to be highly selective for the D1 receptor subtype; more so than its predecessor, [3H]SCH23390. These ligand binds saturably, reversibly and with high affinity. Use of appropriate conditions produces a high signal to noise binding ratio to D1 receptors in slide-mounted tissue sections. Autoradiographic localization of radiolabeled receptors shows high densities of the D1 receptor subtype in such brain structures as the caudate-putamen, nucleus accumbens, entopeduncular nucleus, and the substantia nigra pars reticulata. A lower density of receptors is found in a few other areas including lamina VI of the cerebral cortex. A distinct paucity of binding was apparent in lamina IV of the cerebral cortex and in the choroid plexus, two areas thought to have D1 receptors. SCH39166 thus represents a superior ligand for obtaining selective labeling of D1 receptors in autoradiographic and binding studies.
Neuropsychiatric Research Institute, Fargo, ND.
J K
JK
Wamsley
M E
ME
Alburges
R D
RD
McQuade
M
M
Hunt
D000818:Animals; D001345:Autoradiography; D001552:Benzazepines / Q000494:pharmacology*; D001921:Brain / Q000166:cytology / Q000378:metabolism*; D018492:Dopamine Antagonists / Q000494:pharmacology*; D006801:Humans; D009474:Neurons / Q000378:metabolism; D017447:Receptors, Dopamine D1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014018:Tissue Distribution; D014316:Tritium
D001552:Benzazepines; D018492:Dopamine Antagonists; D017447:Receptors, Dopamine D1; C058081:ecopipam; D014316:Tritium