The Role of Potassium Channels in the Vasodilatation Induced by Resveratrol and Naringenin in Isolated Human Umbilical Vein

Preclinical ResearchPotassium (K + ) channels have a key role in the maintenance of smooth muscle tone; a variety of agonists can modify the tone by altering K + ‐channel activity. The aim of this study was assess the effects of the phenols, resveratrol, and naringenin on K + ‐channels of the vascular smooth muscle. Segments of human umbilical vein (HUV) without endothelium were precontracted using serotonin (100 μM) or 100 mM K + to derive cumulative concentration‐response curves using increasing concentrations of resveratrol or naringenin. K + ‐channel inhibitors were added in the bath before resveratrol (1–100 μM) or naringenin (0.01–1 mM) in assess the role of K + ‐channels in their effects on HUV precontracted by serotonin. 4‐Aminopiridine (4‐AP; 1 mM), a nonselective blocker of voltage‐dependent, tetraethylammonium (TEA; 1 mM) and barium chloride (1 mM), a nonselective blocker of Ca 2+ ‐dependent and inward rectifier K + ‐channels (respectively) induced significant shifts to the right ( P < 0.05) of resveratrol. concentration‐response curves. The effect of naringenin was antagonized by 4‐AP (1 mM). 4‐AP‐, TEA‐, and barium chloride‐sensitive K + ‐channels are probably involved in the resveratrol vasodilatatory effect, while naringenin seems to affect 4‐AP‐sensitive K + ‐channels. However, other mechanisms of vasodilation induced by polyphenols could not be excluded. Drug Dev Res 76 : 17–23, 2015