A novel loop diuretic, torasemide, inhibits thromboxane A2-induced contraction in the isolated canine coronary artery.
We examined the effect of a novel antihypertensive diuretic, torasemide, on the vasoconstriction induced by TXA2 in the isolated canine coronary artery. Carbocyclic thromboxane A2 (CTA2), a stable analogue of the potent coronary vasoconstrictor thromboxane A2, exhibited a slow onset and progressive contraction of isolated canine coronary arteries at 2 x 10(-8) M. Torasemide (10(-7) approximately 10(-4) M) elicited a dose-dependent vasodilating action in the isolated canine coronary arteries contracted by CTA2, whereas indapamide or furosemide had little effect on this preparation. The maximum vasodilating response to torasemide was 45 +/- 12% of vasodilating effect induced by 10(-4) M papaverine. These results suggest that torasemide is a promising antihypertensive agent with a coronary protective effect.
Uchida
T
T
Central Research Laboratory, Green Cross Corporation, Osaka, Japan.
Kido
H
H
Yamanaga
K
K
Okita
M
M
Watanabe
M
M
D000818:Animals; D003331:Coronary Vessels / Q000187:drug effects*; D004232:Diuretics / Q000494:pharmacology; D004285:Dogs; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D013449:Sulfonamides / Q000494:pharmacology*; D013928:Thromboxane A2 / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D000077786:Torsemide; D014661:Vasoconstriction / Q000187:drug effects*; D014664:Vasodilation / Q000187:drug effects
D004232:Diuretics; D013449:Sulfonamides; D013928:Thromboxane A2; D000077786:Torsemide