U-46619-induced potentiation of noradrenergic constriction in the human saphenous vein: antagonism by thromboxane receptor blockade

• Published in: Cardiovascular research 2001-12, Vol.52 (3), p.462-467
• Main Authors: VILA, José M, MARTINEZ-LEON, Juan B, MEDINA, Pascual, SEGARRA, Gloria, BALLESTER, Rosa M, OTERO, Eduardo, LLUCH, Salvador
• Format: Article
• Language: English
• Subjects: 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid - pharmacology; Aged; Biological and medical sciences; Calcium Channel Blockers - pharmacology; Cardiovascular system; Dihydropyridines - metabolism; Dose-Response Relationship, Drug; Drug Synergism; Electric Stimulation; Endothelium, Vascular - drug effects; Endothelium, Vascular - metabolism; Female; Humans; In Vitro Techniques; Male; Medical sciences; Middle Aged; Nifedipine - pharmacology; Norepinephrine - pharmacology; Pharmacology. Drug treatments; Potassium Chloride - pharmacology; Receptors, Thromboxane - antagonists & inhibitors; Saphenous Vein; Stimulation, Chemical; Thromboxane A2 - analogs & derivatives; Thromboxane A2 - pharmacology; Vascular wall; Vasoconstrictor Agents - pharmacology
• ISSN: 0008-6363; 1755-3245
• DOI: 10.1016/S0008-6363(01)00390-X

We investigated the potentiating effect of U-46619, a synthetic analogue of thromboxane A(2) (TXA(2)), on the adrenergic responses in human saphenous vein. Saphenous vein rings were obtained from 35 patients undergoing coronary artery bypass surgery. The rings were suspended in organ bath chambers for isometric recording of tension. U-46619 (10(-10)-3 x 10(-7) mol/l) produced concentration-dependent and endothelium-independent contractile responses. U-46619 (10(-10) mol/l) potentiated the contractions elicited by electrical stimulation and potassium chloride, and produced leftward shifts of the concentration-response curve for noradrenaline. The TXA(2) receptor antagonist SQ-30741 (10(-8) mol/l) prevented the potentiation evoked by U-46619. The dihydropyridine calcium antagonist nifedipine (10(-6) mol/l) did not affect the potentiation of electrical stimulation and noradrenaline induced by U-46619, but abolished the potentiation of U-46619 on KCl-induced contractions. U-46619 facilitates sympathetic neurotransmission and potentiates constrictor effects of noradrenaline in human saphenous veins through stimulation of TXA(2) receptors. These effects are independent of calcium entry through dihydropyridine calcium channels.