Hydrogen peroxide constricts rat arteries by activating Na+-permeable and Ca2+-permeable cation channels.

Hydrogen peroxide constricts rat arteries by activating Na+-permeable and Ca2+-permeable cation channels. Free Radic Res. 2018 Dec 10;:1-171 Authors: Park HJ, Shin KC, Yoou SK, Kang M, Gon Kim J, Jun Sung D, Yu W, Lee Y, Hea Kim S, Min Bae Y, Park SW Abstract Oxidative stress is associated with many cardiovascular diseases, such as hypertension and arteriosclerosis. Oxidative stress reportedly activates the L-type voltage-gated calcium channel (VDCCL) and elevates [Ca2+]i in many cells. However, how oxidative stress activates VDCCL under clinical setting and the consequence for arteries are unclear. Here, we examined the hypothesis that hydrogen peroxide (H2O2) regulates membrane potential (Em) by altering Na+ influx through cation channels, which consequently activates VDCCL to induce vasoconstriction in rat mesenteric arteries. To measure the tone of the endothelium-denuded arteries, a conventional isometric organ chamber was used. Membrane currents and Em were recorded by the patch-clamp technique. [Ca2+]i and [Na+]i were measured with microfluorometry using Fura2-AM and SBFI-AM, respectively. We found that H2O2 (10 and 100 µM) increased arterial contraction, and nifedipine blocked the effects of H2O2 on isometric contraction. H2O2 increased [Ca2+]i as well as [Na+]i, and depolarized Em. Gd3+ (1 µM) blocked all these H2O2-induced effects including Em depolarization and increases in [Ca2+]i and [Na+]i. Although both nifedipine ...
Source: Free Radical Research - Category: Research Tags: Free Radic Res Source Type: research