title: Blockade of dopamine receptors in the renal vasculature by isomers of flupenthixol and sulpiride.
abstract: We studied the renal vascular effects of flupenthixol and sulpiride isomers in the isolated perfused rat kidney in the presence of phenoxybenzamine (10(-5) M) and sotalol (10(-5) M). The vascular bed was contracted with prostaglandin F2 alpha (10(-7) -3 X 10(-6) M) and dose-dependently relaxed with dopamine. Cis-flupenthixol (10(-9)-10(-7) M) antagonized competitively the response to dopamine (apparent pA2 = 8.34 +/- 0.09; mean +/- SD) without affecting papaverine-induced relaxation. Trans-flupenthixol was without effect at 10(-7) M. The dopamine receptor antagonist activities of the sulpiride isomers are low and d-sulpiride is twice as active as 1-sulpiride. Thus, the renal vascular dopamine receptor can be further characterized by the relative antagonist activities of cis-flupenthixol and sulpiride and by a rather low stereospecificity in favor of d-sulpiride.
mesh_terms: D000818:Animals; D002069:Butaclamol / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005475:Flupenthixol / Q000494:pharmacology*; D008297:Male; D010208:Papaverine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects*; D012079:Renal Circulation / Q000187:drug effects*; D013237:Stereoisomerism; D013469:Sulpiride / Q000494:pharmacology*; D013892:Thioxanthenes / Q000494:pharmacology*
chemical_list: D011954:Receptors, Dopamine; D013892:Thioxanthenes; D013469:Sulpiride; D002069:Butaclamol; D010208:Papaverine; D005475:Flupenthixol