Thymoquinone causes endothelium-dependent augmentation of contraction depending on activation of soluble guanylyl cyclase in isolated arteries

Abstract

INTRODUCTION: Experiments were designed to determine the effects of thymoquinone, an alkaloid with in vivo vasodilator properties, in isolated arteries. METHODS: Rings, with or without endothelium, of rat mesenteric arteries, rat aorta and porcine coronary arteries were suspended in conventional organ chambers for isometric tension recording. Certain rings were incubated with inhibitors of nitric oxide (NO) synthase inhibitor (L-N^G-nitroarginine methyl ester, L-NAME) or soluble guanylyl cyclase (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, ODQ). They were contracted with phenylephrine (rat arteries) or prostaglandin F_2alpha (porcine coronary arteries) and exposed to increasing ...