Endothelium-Dependent Contractions of Isolated Arteries to Thymoquinone Require Biased Activity of Soluble Guanylyl Cyclase with Subsequent Cyclic IMP Production.

Preliminary experiments on isolated rat arteries demonstrated that thymoquinone, a compound widely used for its antioxidant properties and believed to facilitate endothelium-dependent relaxations, as a matter of fact caused endothelium-dependent contractions. The present experiments were designed to determine the mechanisms underlying this unexpected response. Isometric tension was measured in rings (with and without endothelium) of rat mesenteric arteries and aortae and of porcine coronary arteries.