No evidence of vascular dopamine receptors in the rat portal vein.
Dopamine (5.3 X 10(-6) to 5.3 X 10(-5) M) decreased the force of spontaneous myogenic contractions of the rat portal vein in a concentration-dependent manner in the presence of the alpha-adrenoreceptor antagonist BE-2254. The DA1-selective agonist fenoldopam and the DA2-preferential agonist (-)-EOE were both inactive. Dopamine-induced relaxation was not inhibited by (+)-butaclamol (10(-8) M), but was reduced by a potent beta 2-selective adrenoreceptor antagonist ICI 118,551 (2 X 10(-8) M). Our results demonstrate that the rat portal vein is devoid of postsynaptic DA1 and DA2 dopamine receptors.
Vidal-Beretervide
K
K
Institut de Pharmacologie et de Médicine Expérimentale (UA 589 CNRS), Strasbourg, France.
Decker
N
N
Schmidt
M
M
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D002069:Butaclamol / Q000494:pharmacology; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D011169:Portal Vein / Q000187:drug effects / Q000378:metabolism; D011412:Propanolamines / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000378:metabolism*
D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; D011954:Receptors, Dopamine; C026777:ICI 118551; D002069:Butaclamol; D007545:Isoproterenol