Development of inhibitory activity of sulpiride for synaptic [3H]-spiperone binding in the rat striatum.
To establish the functional development of striatal dopamine2 (DA2) receptors, the effects of NA+ and GTP on the potency of sulpiride in competing for specific [3H]-spiperone binding were investigated in the striatum of developing rats. The IC50 value of sulpiride for specific [3H]-spiperone binding was 31-fold decreased by 100 mM Na+ compared to that in 70-day-old control animals but not by 50 microM GTP. In the presence of Na+, the IC50 of sulpiride was low in fetuses at 18 days of gestation and high at 360 days of postnatal life. It is suggested that the Na+-dependent binding of sulpiride to DA2 receptors probably reaches functional maturity in fetuses at 18 days of gestation and that the Na+ dependence of the effect decreases during aging.
D000375:Aging; D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects; D002090:Butyrophenones / Q000037:antagonists & inhibitors*; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D006160:Guanosine Triphosphate / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects / Q000378:metabolism*; D012964:Sodium / Q000494:pharmacology; D013134:Spiperone / Q000037:antagonists & inhibitors* / Q000378:metabolism; D013469:Sulpiride / Q000378:metabolism*; D013569:Synapses / Q000187:drug effects / Q000378:metabolism*
D002090:Butyrophenones; D011954:Receptors, Dopamine; D013134:Spiperone; D013469:Sulpiride; D006160:Guanosine Triphosphate; D012964:Sodium