Inhibitory Effects of Cyclopiazonic Acid on the Pacemaker Current in Sinoatrial Nodal Cells
Inhibitory Effects of Cyclopiazonic Acid on the Pacemaker Current in Sinoatrial Nodal Cells
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环匹阿尼酸对窦房结细胞起搏电流的抑制作用
DOI：
10.1016/j.neuroscience.2020.01.018
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发表时间：
2020-01
期刊：
影响因子：
3.3
通讯作者：
Jian-Cheng Zhang
中科院分区：
文献类型：
--
作者：
Qian Chen;Jian-Quan Chen;Pengli Zhu;Hong-Lin Wu;Xiao-Ting Xie;Ying Dong;Guo-jian Xiang;Mei-Yan Chen;Yang Li;Jian-Cheng Zhang
离体窦房结细胞的自发动作电位受钙钟和膜钟的耦合时钟系统调控。然而，目前尚不清楚钙时钟抑制剂是否对膜时钟有直接影响。本研究的目的是研究选择性钙时钟抑制剂环匹阿尼酸（CPA）对SAN细胞膜时钟功能的直接作用。通过胰蛋白酶消化分离SAN细胞，并基于形态学和电生理学鉴定。cells.at通过膜片钳技术记录If和HCN电流。Western blotting检测HCN通道蛋白的表达，10 μM CPA可降低自发动作电位的舒张期去极化率和If电流密度。CPA的抑制作用呈浓度依赖性，IC 50值为16.3 μM，Hill系数为0.98。CPA对If电流的影响也具有时间依赖性，冲洗后If电流幅值部分恢复。此外，If电流的稳态激活曲线移至负电位，表明通道激活减慢。CPA可显著下调HEK293细胞HCN 4蛋白的表达，表明CPA对SAN细胞If电流的直接抑制作用具有浓度和时间依赖性。其潜在机制可能涉及减慢稳态激活和下调起搏通道蛋白的表达。
The spontaneous action potential of isolated sinoatrial node (SAN) cells is regulated by a coupled-clock system of two clocks: the calcium clock and membrane clock. However, it remains unclear whether calcium clock inhibitors have a direct effect on the membrane clock. The purpose of this study was to investigate the direct effect of cyclopiazonic acid (CPA), a selective calcium clock inhibitor, on the function of the membrane clock of SAN cells.at SAN cells were isolated by trypsinization and identified based on morphology and electrophysiology. If and HCN currents were recorded via patch clamp technique. The expression of the HCN channel protein was determined by Western blotting analysis.The diastolic depolarization rate of spontaneous action potentials and the current densities of If were reduced by exposure to 10 μM CPA. The inhibitory effect of CPA was concentration-dependent with an IC50 value of 16.3 μM and a Hill coefficient of 0.98. The effect of CPA on If current was also time-dependent, and the If current amplitude was partially restored after washout. Furthermore, the steady-state activation curve of the If current was shifted to a negative potential, indicating that channel activation slowed down. Finally, the protein expression of HCN4 in HEK293 cells was markedly downregulated by CPA.These results indicate that the direct inhibition effect of CPA on the If current in SAN cells is both concentration- and time-dependent. The underlying mechanisms may involve slowing down steady-state activation and the downregulation of pacemaker channel protein expression.
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影响因子：
5
作者：
Yaniv, Yael;Sirenko, Syevda;Ziman, Bruce D.;Spurgeon, Harold A.;Maltsev, Victor A.;Lakatta, Edward G.
通讯作者：
Lakatta, Edward G.
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5
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Hüser, J;Blatter, LA;Lipsius, SL
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Lipsius, SL
影响因子：
158.5
作者：
Milanesi, R;Baruscotti, M;DiFrancesco, D
通讯作者：
DiFrancesco, D
影响因子：
4
作者：
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通讯作者：
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