Effect of epinine on tension of human renal arteries.
BACKGROUND
The present study aimed to characterize the effects of epinine, the active metabolite of ibopamine on tension development in human renal arteries.


RESULTS
Experiments were performed on isolated human renal arteries rings obtained during surgery due to kidney tumors (n = 12). Epinine concentration-dependently relaxed isolated precontracted (PGF2 alpha) human renal artery rings (P < 0.05) in the presence of phentolamine, as effectively (epinine -30 +/- 4 mN, dopamine -31 +/- 5 mN) and with the same potency as dopamine (epinine EC50 0.7 mumol/l (0.4-1.2 mumol/l), dopamine 0.5 mumol/l (0.2-1.7 mumol/l). This effect was antagonized by the specific D1-receptor-antagonist SCH 23390. Effective beta-adrenoceptor antagonistic concentrations of propranolol did not affect epinine-induced vasorelaxation. In the absence of alpha- and beta-adrenoceptor-antagonists the potency of epinine to contract renal artery rings was significantly higher compared to dopamine indicating a higher affinity of epinine to alpha-adrenoceptors.


CONCLUSIONS
The present study provides evidence for direct vasodilatory effects of epinine via activation of D1-receptors on human renal arteries.
Schwinger
R H
RH
Klinik III für Innere Medizin, Universität zu Köln, Germany.
Schulz
C
C
Brixius
K
K
Böhm
M
M
Müller-Ehmsen
J
J
Erdmann
E
E
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D001552:Benzazepines / Q000494:pharmacology; D003846:Deoxyepinephrine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D004298:Dopamine / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006801:Humans; D009119:Muscle Contraction / Q000187:drug effects*; D010646:Phentolamine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D012077:Renal Artery / Q000187:drug effects*; D014664:Vasodilation / Q000187:drug effects
D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists; D001552:Benzazepines; D018492:Dopamine Antagonists; D011433:Propranolol; D003846:Deoxyepinephrine; D004298:Dopamine; D010646:Phentolamine