Exercise Training Reverses Alterations in K-v and BKCa Channel Molecular Expression in Thoracic Aorta Smooth Muscle Cells from Spontaneously Hypertensive Rats

摘要

Previous studies have shown that exercise training influences potassium channel protein expression in arteries. The purpose of this study was to investigate the effect of exercise training on alterations in voltage-gated potassium channels (K-v) and large-conductance, calcium-activated potassium channels (BKCa) in thoracic aorta smooth muscle cells from spontaneously hypertensive rats (SHRs). Male SHRs were randomly assigned to a sedentary group (SHR-SED) and exercise training group (SHR-EX). Age-matched Wistar-Kyoto rats (WKYs) were used as controls. After 8 weeks of aerobic exercise training, blood pressure was significantly lower in the SHR-EX group than in the SHR-SED group. Exercise training increased the contribution of the K(v)1.2 and K(v)1.5 channels and decreased the contribution of BKCa channel to resting tone in the SHR-EX group compared to the SHR-SED group as indicated by vessel contractility experiments. Imnnunohistochemistry and Western blotting showed that K(v)1.2 and K(v)1.5 channel expression was significantly lower in the SHR-SED group than in the WKY group and exercise training attenuated this reduction. BKCa alpha-subunit expression was statistically unchanged between the groups; however, beta 1-subunit expression was reduced significantly by exercise training in the SHR-EX group compared to the SHR-SED group. These data suggest that exercise training reverses the pathological expression of the K(v)1.2, K(v)1.5, and BKCa channels in aortic myocytes from SHRs. This is one of the favorable effects of exercise training on large conduit arteries. (C) 2015 S. Karger AG, Basel