Electrical properties and response to noradrenaline of individual heart cells isolated from human ventricular tissue.
Electrical properties and response to noradrenaline of individual heart cells isolated from human ventricular tissue.
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从人心室组织中分离出的单个心脏细胞的电特性和对去甲肾上腺素的反应。
DOI：
10.1093/cvr/20.12.869
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发表时间：
1986
影响因子：
10.8
通讯作者：
Twist,VW
中科院分区：
文献类型：
--
作者：
Mitchell,MR;Powell,T;Sturridge,MF;Terrar,DA;Twist,VW
通过使用单细胞制剂，大大简化了心脏组织的电特性和儿茶酚胺反应的分析。在这项研究中，使用从人心室组织中分离出的单个细胞来估计细胞肌膜电阻和电容，并记录对离子导入去甲肾上腺素的反应的时间过程。如果比膜电容为 1 μF·cm−2，则电池的平均输入电容与约 15000 μm2 的表面膜面积一致。这比测量的细胞外部尺寸所预期的要大，并且与表面膜折叠和小凹的存在相一致。在膜电位接近-75 mV时，平均细胞输入电阻约为40 MΩ，如果平均膜面积为15000 μm2，则比膜电阻为6 kΩ·cm2，并且与所用实验条件下分离的细胞具有密封闰盘的假设一致。离子电渗疗法应用的去甲肾上腺素使动作电位的平台期显着延长，但这种效应会持续很多秒。缓慢起效与儿茶酚胺自由细胞外扩散的动力学不相容，但可能反映了去甲肾上腺素与膜受体结合和最终细胞反应之间发生的分子事件。在电压钳条件下，细胞表现出时间依赖性内向电流，与肌膜钙电导的快速激活和衰减一致。
The analysis of the electrical properties and response to catecholamines of cardiac tissue is greatly simplified by the use of single cell preparations. In this study individual cells isolated from human ventricular tissue were used to estimate cellular sarcolemmal resistance and capacitance and to record the time course of the response to ionophoretically applied noradrenaline. The mean input capacitance of the cells is consistent with a surface membrane area of approximately 15000 μm2if the specific membrane capacitance is 1 μF·cm−2. This is larger than might be expected from the measured external dimensions of the cell and is compatible with the presence of surface membrane infoldings and caveolae. At membrane potentials close to −75 mV the mean cell input resistance was approximately 40 MΩ, giving a specific membrane resistance of 6 kΩ·cm2if mean membrane area is 15000 μm2and consistent with the assumption that the isolated cells have sealed intercalated discs under the experimental conditions used. Ionophoretically applied noradrenaline produced a pronounced prolongation of the plateau phase of the action potential, but this effect developed over many seconds. The slow onset of action is not compatible with the kinetics of free extracellular diffusion of catecholamine but may reflect molecular events that occur between noradrenaline binding to membrane receptors and the final cellular response. Under voltage-clamp conditions, the cells showed a time dependent inward current consistent with the rapid activation and decay of a sarcolemmal calcium conductance.