Oscillatory membrane potential response to glucose in islet β-cells:: A comparison of islet-cell electrical activity in mouse and rat
Oscillatory membrane potential response to glucose in islet β-cells:: A comparison of islet-cell electrical activity in mouse and rat
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DOI：
10.1210/en.2006-0424
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发表时间：
2006-10-01
期刊：
影响因子：
4.8
通讯作者：
Wheeler, Michael B.
中科院分区：
文献类型：
--
作者：
Fox, Jocelyn E. Manning;Gyulkhandanyan, Armen V.;Wheeler, Michael B.
与小鼠相反，据报道大鼠胰岛β细胞膜电位不响应于升高的葡萄糖而振荡，尽管证明了钙和胰岛素分泌的振荡。我们的目的是阐明大鼠胰岛β细胞的电活动，并表征和比较大鼠和小鼠胰岛中α细胞和β细胞的电活动。我们使用穿孔全细胞膜片钳技术记录了小鼠和大鼠完整胰岛内α和β细胞的电活动。五十六%的小鼠和大鼠β细胞对11.1 mM葡萄糖表现出振荡反应。11.1 mM和2.8 mM葡萄糖的反应在两个物种中是相同的。大鼠β细胞以葡萄糖浓度依赖性方式表现出增量去极化。我们还证明了在相同条件下记录的人类胰岛的电活动。在小鼠和大鼠α细胞中，11 mM葡萄糖引起膜电位超极化，而2.8 mM葡萄糖产生动作电位放电。在α细胞对葡萄糖的反应中未观察到种属差异。本文是第一个证明和表征振荡膜电位波动的存在下，葡萄糖升高的大鼠胰岛α细胞与小鼠相比。这些发现促进了大鼠胰岛在未来电生理学研究中的应用，使电生理学和胰岛素分泌研究之间保持一致。α-细胞膜电位对葡萄糖的逆反应进一步加深了我们对葡萄糖敏感性胰高血糖素分泌机制的理解。
In contrast to mouse, rat islet beta-cell membrane potential is reported not to oscillate in response to elevated glucose despite demonstrated oscillations in calcium and insulin secretion. We aim to clarify the electrical activity of rat islet beta-cells and characterize and compare the electrical activity of both alpha- and beta-cells in rat and mouse islets. We recorded electrical activity from alpha- and beta-cells within intact islets from both mouse and rat using the perforated whole-cell patch clamp technique. Fifty-six percent of both mouse and rat beta-cells exhibited an oscillatory response to 11.1 mM glucose. Responses to both 11.1 mM and 2.8 mM glucose were identical in the two species. Rat beta-cells exhibited incremental depolarization in a glucose concentration-dependent manner. We also demonstrated electrical activity in human islets recorded under the same conditions. In both mouse and rat alpha-cells 11 mM glucose caused hyperpolarization of the membrane potential, whereas 2.8 mM glucose produced action potential firing. No species differences were observed in the response of alpha-cells to glucose. This paper is the first to demonstrate and characterize oscillatory membrane potential fluctuations in the presence of elevated glucose in rat islet alpha-cells in comparison with mouse. The findings promote the use of rat islets in future electrophysiological studies, enabling consistency between electrophysiological and insulin secretion studies. An inverse response of alpha-cell membrane potential to glucose furthers our understanding of the mechanisms underlying glucose sensitive glucagon secretion.