Dopamine induced relaxation of isolated canine renal, mesenteric, and femoral arteries contracted with prostaglandin F2-alpha.
The purpose of this investigation was to develop a system for studying the effects of dopamine on isolated blood vessels. Canine renal, mesenteric, and small femoral arteries (less than 1 mm outside diameter) were exposed to phenoxybenzamine 10-5 M for one hour and contracted with prostaglandin F2-alpha. Cumulative concentrations of dopamine ranging from 10-6 to 10-4 M caused dose-related relaxation of the arteries. Propranolol 10-6 M did not affect the relaxation in concentrations which markedly antagonized the effects of isoproterenol. Large femoral arteries (greater than 1 mm outside diameter) did not relax with similar concentrations of dopamine. N-methyldopamine (epinine) produced similar relaxation; 3-methoxytyramine was inactive. Specific antagonism could not be demonstrated by the postulated dopamine antagonists-haloperidol, chlorpromazine, apomorphine, or bulbocapnine-in concentrations up to 10-5 M. Higher concentration of these agents could not be used because they caused the arteries to relax. This study demonstrated that PGF2-alpha-contracted arteries pretreated with phenoxybenzamine are suitable for further investigations of putative dopamine agonists and antagonists.
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D003846:Deoxyepinephrine / Q000494:pharmacology; D004285:Dogs; D004298:Dopamine / Q000494:pharmacology*; D018492:Dopamine Antagonists; D004305:Dose-Response Relationship, Drug; D005260:Female; D005263:Femoral Artery / Q000187:drug effects*; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects*; D010208:Papaverine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011460:Prostaglandins F / Q000494:pharmacology*; D012077:Renal Artery / Q000187:drug effects*; D011984:Sensory Receptor Cells; D013329:Structure-Activity Relationship; D014666:Vasomotor System / Q000187:drug effects*
D000319:Adrenergic beta-Antagonists; D018492:Dopamine Antagonists; D011460:Prostaglandins F; D011433:Propranolol; D010208:Papaverine; D007545:Isoproterenol; D003846:Deoxyepinephrine; D004298:Dopamine