Voltage-gated and resting membrane currents recorded from B-cells in intact mouse pancreatic islets
Voltage-gated and resting membrane currents recorded from B-cells in intact mouse pancreatic islets
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DOI：
10.1111/j.1469-7793.1999.00717.x
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发表时间：
1999-12-15
影响因子：
5.5
通讯作者：
Rorsman, P
中科院分区：
文献类型：
--
作者：
Göpel, S;Kanno, T;Rorsman, P
1.将膜片钳技术的穿孔膜片全细胞配置应用于完整胰岛中的表面细胞。免疫组化结合共聚焦显微镜观察显示，表层细胞由35%的胰岛素分泌B细胞和65%的非B细胞（A细胞和D细胞）组成.两种类型的细胞，具有不同的电生理特性，可以在功能上进行鉴定。其中之一在胰岛暴露于10 mM葡萄糖时产生振荡电活动，并具有在组织培养中保持的分离B细胞的电生理特征。原位B细胞的Ca ~（2+）电流比分离的B细胞大80%。在100 ms去极化期间，它表现出显著（70%）失活。失活是电压依赖性的，在去极化引起最大的Ca 2+电流时尤为突出.在去极化至膜电位高于-20 mV期间观察到电压依赖性K+电流。这些电流在200 ms去极化期间几乎不失活，并且不受在-90 mV和-30 mV之间改变保持电位的影响。在不存在葡萄糖的情况下，反映ATP调节的K+（K-ATP）通道的电导的最大静息电导相当于4 nS。葡萄糖产生浓度依赖性的K-ATP通道电导降低，在5 mM葡萄糖下观察到半数最大抑制。结合电压和电流钳记录允许估计不同B细胞之间的差距结电导。这些实验表明，在刺激性葡萄糖浓度（类似于1 nS）的B细胞的输入电导几乎完全由耦合到相邻的B细胞。
1. The perforated patch whole-cell configuration of the patch-clamp technique was applied to superficial cells in intact pancreatic islets. Immunostaining in combination with confocal microscopy revealed that the superficial cells consisted of 35% insulin-secreting B-cells and 65 % non-B-cells (A- and D-cells).2. Two types of cell, with distinct electrophysiological properties, could be functionally identified. One of these generated oscillatory electrical activity when the islet was exposed to 10 mM glucose and had the electrophysiological characteristics of isolated B-cells maintained in tissue culture.3. The Ca2+ current recorded from B-cells in situ was 80% larger than that of isolated B-cells. It exhibited significant (70%) inactivation during 100 ms depolarisations. The inactivation was voltage dependent and particularly prominent during depolarisations evoking the largest Ca2+ currents.4. Voltage-dependent K+ currents were observed during depolarisations to membrane potentials above -20 mV. These currents inactivated little during a 200 ms depolarisation and were unaffected by varying the holding potential between -90 and -30 mV.5. The maximum resting conductance in the absence of glucose, which reflects the conductance of ATP-regulated K+ (K-ATP) channels, amounted to similar to 4 nS. Glucose produced a concentration-dependent reduction of K-ATP channel conductance with half-maximal inhibition observed with 5 mM glucose.6. Combining voltage- and current-clamp recording allowed the estimation of the gap junction conductance between different B-cells. These experiments indicated that the input conductance of the B-cell at stimulatory glucose concentrations (similar to 1 nS) is almost entirely accounted for by coupling to neighbouring B-cells.