Vasodilatation Effects and Mechanism of Imperatorin Derivative OW1 / 中国药学杂志

ABSTRACT

OBJECTIVE To investigate vasodilation effect and mechanism of OW1 was investigated on rat aorta, renal artery, cerebral middle artery, coronary artery, pulmonary artery and mesenteric artery. METHODS Isometric tension was measured in a 610 M-DMT Wire Myograph System. 60 mmol·L-1 KCl was added to the baths to induce pre-contraction of the 6 arteries. The concentration-response curves of OW1 were constructed on endothelium-denuded aorta rings or blocking endothelial, beta adrenergic receptor, three potassium channels and changing the concentration of intracellular or external calcium respectively. RESULTS OW1 could relax the 6 arteries completely, and Emax were all above 95%. pEC50 were (6.11±0.09), (5.76±0.01), (6.22±0.08), (5.78±0.05), (5.65±0.01), and (6.59±0.07) respectively. β-Adrenoceptor, ATP sensitive potassium channel and inwardly rectifying potassium channel were not involved in the vasodilatation, whereas blockage of calcium-activated potassium channel with tetraethylammonium had effect. OW1 could inhibit the influx of extracellular calcium and the release of intracellular calcium, thereby inhibiting vasoconstriction. CONCLUSION OW1 could relax the six arteries. The possible mechanisms of the vasodilatation are mainly involved with inhibiting voltage dependent calcium channel and receptor-mediated Ca2+ influx and release, and might be partly due to opening calcium-activated potassium channel.