ATP release by cardiac myocytes in a simulated ischaemia model Inhibition by a connexin mimetic and enhancement by an antiarrhythmic peptide
ATP release by cardiac myocytes in a simulated ischaemia model Inhibition by a connexin mimetic and enhancement by an antiarrhythmic peptide
复制标题
DOI：
10.1016/j.ejphar.2008.12.005
复制
发表时间：
2009-03-01
影响因子：
5
通讯作者：
Evans, W. Howard
中科院分区：
文献类型：
--
作者：
Clarke, Thomas C.;Williams, Oliver J. S.;Evans, W. Howard
我们研究了连接蛋白半通道在缺血应激下新生心肌细胞释放三磷酸腺苷中的作用。机械、渗透和氧化应激以及细胞外或细胞内钙离子水平的变化诱导位于质膜上的连接蛋白半通道开放和释放具有信号潜力的小离子和小分子，如ATP。由于ATP的释放与对缺氧的适应有关，我们研究了在定制的缺氧室中孵育不同时期的心肌细胞的ATP释放。在模拟缺血模型中(0.5%氧气和0.2g/L葡萄糖)，三磷酸腺苷释放的峰值出现在80min，然后恢复到稳态水平，持续200min。在低氧(0.5%氧气，3.0g/L葡萄糖)的心肌细胞中，没有观察到这一ATP释放高峰。两类以缝隙连接通道形成蛋白--连接蛋白为靶点的试剂对缺血时ATP的释放有影响。首先，缝隙连接蛋白半通道抑制剂Gap 26和18a甘草次酸取消了ATP释放峰。AAP10是一种抗心律失常的多肽，能显著增加缺血80min的ATP释放峰，并在180-240min引起第二个较小的峰。检测心肌细胞三磷酸腺苷含量和Cx43磷酸化水平。由于心肌缺血时ATP的释放被连接蛋白通道阻滞剂所抑制，并被一种在心律失常背景下针对连接蛋白的多肽所刺激，结果提示连接蛋白半通道的核苷酸释放可能是心肌细胞对缺血应激的反应的特征。(C)2008爱思唯尔B.V.保留所有权利。
We studied the role of connexin hemichannels in the release of ATP by neonatal cardiac myocytes subject to ischaemic stress. Mechanical, osmotic and oxidative stress and changes in extracellular or intracellular Ca2+ levels induce connexin hemichannels located in the plasma membrane to open and release small ions and molecules with signaling potential such as ATP. Since ATP release has been implicated in adaptation to oxygen deprivation, we studied its release by cardiac myocytes incubated in a custom-built hypoxia chamber for various periods. In a simulated ischaemia model (0.5% oxygen and 0.2 g/l glucose) a peak of ATP release occurred at 80 min followed by a return to steady state levels for a further 200 min. This peak of ATP release was not observed in myocytes subject to hypoxia (0.5% oxygen, 3.0 g/l glucose). ATP release in ischaemia was influenced by two classes of reagents that target connexins, the channel forming proteins of gap junctions. First, the connexin hemichannel inhibitors Gap 26 and 18a glycyrrhetinic acid abolished the ATP peak of release. Second, the AAP10, a peptide with antiarrhythmic properties markedly increased the peak of ATP release observed at 80 min of ischaemia and also induced a second smaller peak at 180-240 min. ATP content of the myocytes and Cx43 phosphorylation were monitored. Since the release of ATP in ischaemia was abolished by connexin channel inhibitors and stimulated by a peptide developed to target connexins in the context of cardiac arrhythmia, the results suggest that nucleotide release by connexin hemichannels is likely to feature in the response of myocytes to ischaemic stress in the heart. (C) 2008 Elsevier B.V. All rights reserved.