Nitric oxide induces apoptosis by activating K + channels in pulmonary vascular smooth muscle cells

作者：Stefanie Krick, Oleksandr Platoshyn, Michèle Sweeney, Sharon S. McDaniel, Shen Zhang, Lewis J. Rubin, Jason X.‐J. Yuan · 发表于：American Journal of Physiology-Heart and Circulatory Physiology · 年份：2002 · DOI：10.1152/ajpheart.2002.282.1.h184 · 被引用次数：73 · 研究领域：Nitric Oxide and Endothelin Effects、Cardiac Ischemia and Reperfusion、Renin-Angiotensin System Studies

Nitric oxide (NO) is an endogenous endothelium-derived relaxing factor that regulates vascular smooth muscle cell proliferation and apoptosis. This study investigated underlying mechanisms involved in NO-induced apoptosis in human and rat pulmonary artery smooth muscle cells (PASMC). Exposure of PASMC to NO, which was derived from the NO donor S-nitroso-N-acetyl-penicillamine, increased the percentage of cells undergoing apoptosis. Increasing extracellular K+ concentration to 40 mM or blocking K+ channels with 1 mM tetraethylammonia (TEA), 100 nM iberiotoxin (IBTX), and 5 mM 4-aminopyridine (4-AP) significantly inhibited the NO-induced apoptosis. In single PASMC, NO reversibly increased K+ currents through the large-conductance Ca(2+)-activated K+ (K(Ca)) channels, whereas TEA and IBTX markedly decreased the K(Ca) currents. In the presence of TEA, NO also increased K+ currents through voltage-gated K+ (K(v)) channels, whereas 4-AP significantly decreased the K(v) currents. Opening of K(Ca) channels with 0.3 mM dehydroepiandrosterone increased K(Ca) currents, induced apoptosis, and further enhanced the NO-mediated apoptosis. Furthermore, NO depolarized the mitochondrial membrane potential. These observations indicate that NO induces PASMC apoptosis by activating K(Ca) and K(v) channels in the plasma membrane. The resulting increase in K+ efflux leads to cytosolic K+ loss and eventual apoptosis volume decrease and apoptosis. NO-induced apoptosis may also be related to mitochond...