Evidence for a dopamine receptor subtype sensitive to combination of D1 with D2 antagonist in measurement of G-protein activity using rat striatal membranes.
In rat striatal membranes, various kinds of dopamine receptor agonists stimulated low-Km GTPase activity in a concentration-dependent manner. This stimulation by bromocriptine, pergolide and apomorphine was partially inhibited by sulpiride (SUL), a D2-selective antagonist, markedly inhibited by combination of SUL with SCH 23390 (SCH), a D1-selective antagonist, and not modified by SCH alone. The stimulation by BAM-1110 was resistant to SUL or SCH alone but abolished by combination of SUL with SCH. These findings suggest the presence of another subtype of a dopamine receptor in a functional in vitro bioassay system in rat striata.
Yue
J L
JL
Department of Pharmacology, Yokohama City University School of Medicine, Japan.
Ueda
H
H
Misu
Y
Y
D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects*; D018492:Dopamine Antagonists; D020558:GTP Phosphohydrolases / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000032:analysis*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D017447:Receptors, Dopamine D1 / Q000187:drug effects*; D017448:Receptors, Dopamine D2 / Q000187:drug effects*
D018492:Dopamine Antagonists; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins