title: Endothelium-independent vasorelaxant effect of lidocaine in rat aortic rings.
abstract: In the present study, lidocaine relaxed, in a concentration-dependent manner, the contractions induced by either phenylephrine or a high concentration of KCl (60 mM) in endothelium-intact rat aortic rings. Mechanical removal of endothelium did not significantly modify lidocaine-induced vasorelaxation. In endothelium-denuded aortic rings depolarized by 60 mM KCl, lidocaine inhibited Ca2+-induced contraction. Lidocaine also reduced the transient contraction elicited by phenylephrine in Ca2+-free medium. Pretreatment of endothelium-denuded aorta nonspecific K+ with tetraethylammonium, a channel blocker, had no effect on the relaxant effect of lidocaine. These results indicate that lidocaine induces an endothelium-independent relaxation in rat aortic rings. The main mechanisms may include suppression in Ca2+ through the voltage-sensitive Ca2+ influx intracellular Ca2+ channels and inhibition of release in the vascular smooth muscle cells.
authors.affiliation: Department of Physiology, Zhejiang University School of Medicine, Hangzhou 310031, P. R. China.
authors.forename: Q-X
authors.initials: QX
authors.lastname: Shan
authors.forename: D-S
authors.initials: DS
authors.lastname: Lin
authors.forename: H-F
authors.initials: HF
authors.lastname: Jin
authors.forename: Q
authors.initials: Q
authors.lastname: Gao
authors.forename: Y
authors.initials: Y
authors.lastname: Lu
authors.forename: Q
authors.initials: Q
authors.lastname: Xia