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Analysis of the Gating Mechanism of Cardiac Ca Channel by Long Recorder

长记录仪分析心脏Ca通道门控机制

基本信息

批准号：
02670041
负责人：
OCHI Rikuo
金额：
$ 1.41万
依托单位：
Juntendo University School of Medicine
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02670041/
关键词：
Ca channel availability isoprenaline BAY K 8644 patch clamp cardiac muscle パッチクランプ法 BAY K 8644 燐酸化

项目摘要

The sympathetic catecholamines increase L-type Ca current in cardiac muscle. Hitherto single channel studies with patch clamp technique have established that the increase is due to an increase in the total open probability determined by the rate of current-containing sweeps (availability, Ps). Present study concerns with the problem how the beta-agonists modify Ps and the open probability in each current-containing sweep (Po). Ventricular myocytes were isolated enzymatically from guinea-pig and superfused with high-K aspartate solution. Single Ca channel currents were recorded from cell-attached patches containing only one functionally active channel by 100 mm Ba-containing pipettes. ISO were added to the superfusate and BAY K 8644 was applied either to the perfusate or to the pipette solution. Isoprenaline (ISO) at 100 nM modulated ecusively slow gating processes of the Ca channel and increased Ps. ISO increased excusively Ps even at 0.01 mM and 0.1 mM. The major changes at these high concentration was the increase in Ps similarly with 100 nM. In the presence of BAY K 8644 ISO again increased the channel availability. We found that ISO also increases Po in the nonblank sweeps in the presence of BAY K. Po was increased by ISO by about 60% at 100 nM. Thus, the channel phosphorylation may favor the binding of dihydropyridine drugs to the channel.

交感神经儿茶酚胺增加心肌L型钙电流。采用膜片钳技术进行的高电压单通道研究已经确定，这种增加是由于由含电流扫描速率（可用性，Ps）确定的总开放概率增加所致。本研究关注的问题是β-受体激动剂如何改变Ps和在每个含电流扫描中的开放概率（Po）。用酶法分离豚鼠心室肌细胞，用高钾天冬氨酸溶液灌流。通过100 mm含Ba移液器从仅含有一个功能活性通道的细胞贴附贴片记录单个Ca通道电流。将ISO加入到灌注液中，并将BAY K 8644施加到灌注液或移液管溶液中。异丙肾上腺素（ISO）在100 nM调制ecusively缓慢门控过程的钙通道和增加Ps。即使在0.01 mM和0.1 mM时，ISO也能显著增加Ps。在这些高浓度下的主要变化是Ps的增加，与100 nM相似。在湾K 8644 ISO的存在再次增加了渠道的可用性.我们发现，ISO也增加了PO在非空白扫描在BAY K的存在。在100 nM下，ISO使Po增加约60%。因此，通道磷酸化可能有利于二氢吡啶类药物与通道的结合。