The vasodilatory effects of hydralazine, nicardipine, nitroglycerin, and fenoldopam in the human umbilical artery.
We studied the effects of hydralazine, nicardipine, nitroglycerin, and fenoldopam (a dopamine D1-agonist) on isolated human umbilical arteries (HUA) from patients classified as normotensive and with pregnancy-induced hypertension (PIH). Umbilical artery rings were contracted with the thromboxane A(2) analog (U46619; 10(-8) M) and then exposed to cumulative concentrations of fenoldopam, hydralazine, nicardipine, and nitroglycerin. Second, rings were preexposed to prazosin (10(-5) M), phenoxybenzamine (10(-5) M), or none, and the constriction responses to increasing doses of fenoldopam or dopamine were recorded. Nitroglycerin, hydralazine, and nicardipine produced concentration-dependent relaxation of U46619-preconstricted HUA segments from normotensive and PIH patients. Fenoldopam and dopamine induced umbilical artery constriction in both normal and PIH rings at concentrations > or = 10(-5) M and > or = 10(-3) M, respectively. Phenoxybenzamine, but not prazosin, pretreatment irreversibly abolished fenoldopam-induced contraction. In this in vitro study, nitroglycerin was the most potent vasodilator of the HUA constricted with U46619, followed by nicardipine and hydralazine. However, fenoldopam constricted HUA rings only at supratherapeutic concentrations. No significant differences of vascular responses to fenoldopam (P = 0.3534), nitroglycerin (P = 0.7416), nicardipine (P = 0.0615), and hydralazine (P = 0.5514) between rings from normotensive or hypertensive pregnant patients were shown.
Sato
Nobukazu
N
Department of Anesthesiology, Emory University School of Medicine, Division of Cardiothoracic Anesthesia and Critical Care, Emory Healthcare, Atlanta, USA.
Tanaka
Kenichi A
KA
Szlam
Fania
F
Tsuda
Atsushi
A
Arias
Maria E
ME
Levy
Jerrold H
JH
D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / Q000494:pharmacology; D004298:Dopamine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D018818:Fenoldopam / Q000494:pharmacology*; D006801:Humans; D006830:Hydralazine / Q000494:pharmacology*; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009529:Nicardipine / Q000494:pharmacology*; D005996:Nitroglycerin / Q000494:pharmacology*; D011189:Potassium Chloride / Q000494:pharmacology; D011225:Pre-Eclampsia / Q000503:physiopathology; D011247:Pregnancy; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects; D013928:Thromboxane A2 / Q000494:pharmacology; D014469:Umbilical Arteries / Q000187:drug effects*; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology*
D011942:Receptors, Adrenergic, alpha; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D006830:Hydralazine; D013928:Thromboxane A2; D011189:Potassium Chloride; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D009529:Nicardipine; D005996:Nitroglycerin; D018818:Fenoldopam; D004298:Dopamine