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

Preclinical Research Potassium (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 Ca2+ -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