Turnover of specific [3H]spiperone and [3H]N,n-propylnorapomorphine binding sites in rat striatum following phenoxybenzamine administration.
Inclusion of phenoxybenzamine into incubates containing rat striatal preparations equipotently displaced specific striatal [3H]spiperone and [3H]NPA binding. Pre-incubation of striatal membranes with phenoxybenzamine followed by extensive washing equipotently inhibited the subsequent specific [3H]spiperone or [3H]NPA binding. In both displacement and pre-incubation experiments phenoxybenzamine caused complete inhibition of specific [3H]spiperone binding to rat striatal membranes, but only partially inhibited specific [3H]NPA binding. Following parenteral administration to rats, phenoxybenzamine caused a marked inhibition of ex vivo specific [3H]spiperone binding in striatal tissue preparations from these animals which lasted approximately 24 hr following in vivo drug administration. In contrast, administration of phenoxybenzamine caused only a transient change in ex vivo specific [3H]NPA binding. Phenoxybenzamine causes irreversible inhibition of [3H]spiperone and [3H]NPA binding in vitro. In vivo administration of phenoxybenzamine discriminates between [3H]spiperone and [3H]NPA in ex vivo studies suggesting that these binding sites have different turnover rates.
D000818:Animals; D001058:Apomorphine / Q000031:analogs & derivatives* / Q000378:metabolism; D001665:Binding Sites; D001667:Binding, Competitive; D002090:Butyrophenones / Q000378:metabolism*; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D007700:Kinetics; D010643:Phenoxybenzamine / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000378:metabolism*; D013134:Spiperone / Q000378:metabolism*
D002090:Butyrophenones; D011954:Receptors, Dopamine; C031611:spiroperidol receptor; D010643:Phenoxybenzamine; D013134:Spiperone; C009074:N-n-propylnorapomorphine; D001058:Apomorphine