Hydrogen peroxide stimulates the Ca2+-activated big-conductance K channels (BK) through cGMP signaling pathway in cultured human endothelial cells
Hydrogen peroxide stimulates the Ca2+-activated big-conductance K channels (BK) through cGMP signaling pathway in cultured human endothelial cells
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DOI：
10.1159/000149789
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发表时间：
2008-01-01
影响因子：
--
通讯作者：
Wang, Wen-Hui
中科院分区：
文献类型：
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作者：
Dong, De-Li;Yue, Peng;Wang, Wen-Hui
采用全细胞膜片钳技术研究了过氧化氢（H_2O_2）对人内皮细胞钙激活的BK通道的影响。我们证实了先前的发现，即当细胞膜电位被钳位在50 mV时，检测到200 pS BK通道活性。应用H2 O2或加入葡萄糖氧化酶（GO）刺激BK通道。用活性氧清除剂ebselen处理的细胞中不存在H2 O2和GO的刺激作用。为了确定H2 O2和GO对BK通道的刺激作用是否是增加内皮细胞中NO产生的结果，我们在存在抑制NO合酶（NOS）的0.1 mM L-NAME的情况下检测了H2 O2和GO对BK通道的作用。抑制NOS可完全阻断H_2O_2对BK通道的兴奋作用。相反，用D-NAME处理内皮细胞并不能阻断H2 O2对BK通道的作用。用ODQ抑制可溶性鸟苷酸环化酶（sGC）可模拟L-NAME的作用，并消除H_2O_2的作用。在cGMP类似物存在下，加入8-溴-cGMP刺激BK通道和进一步应用H_2O_2并不增加BK通道活性。H_2O_2对BK通道的作用是通过刺激NO-cGMP途径的结果，这一观点进一步通过观察到用KT 5823抑制PKG也消除了H_2O_2对BK通道的刺激作用而得到证实。结论：H2 O2通过NO/sGC/cGMP途径刺激培养的人内皮细胞Ca ~（2+）BK通道。版权所有（C）2008 S. Karger AG，巴塞尔。
We used the whole cell patch-clamp technique to examine the effect of hydrogen peroxide (H2O2) on the Ca2+-activated BK channels in human endothelial cells. We confirmed the previous finding that a 200 pS BK channel activity was detected when the cell membrane potential was clamped at 50 mV. Application of H2O2 or adding glucose oxidase (GO) stimulated BK channels. The stimulatory effect of H2O2 and GO was absent in cells treated with ebselen, a scavenger of reactive oxygen species (ROS). To determine whether the stimulatory effect of H2O2 and GO on BK channels is the result of increasing NO production in the endothelial cells, we examined the effect of H2O2 and GO on BK channels in the presence of 0.1 mM L-NAME which inhibits NO synthase (NOS). Inhibition of NOS completely abolished the stimulatory effect of H2O2 on BK channels. In contrast, treatment of endothelial cells with D-NAME did not block the effect of H2O2 on BK channels. Moreover, inhibiting soluble guanylate cyclase (sGC) with ODQ mimicked the effect of L-NAME and abolished the effect of H2O2. Addition of 8-bromo-cGMP stimulated BK channels and further application of H2O2 did not increase BK channel activity in the presence of cGMP analog. The notion that the effect of H2O2 on BK channels was the result of stimulating NO-cGMP pathway is further indicated by the observation that inhibition of PKG with KT5823 also abolished the stimulatory effect of H2O2 on BK channels. We conclude that H2O2 stimulates the Ca2+ BK channels through NO/sGC/cGMP pathway in cultured human endothelial cells. Copyright (C) 2008 S. Karger AG, Basel.