Patch-clamp characterisation of somatostatin-secreting δ-cells in intact mouse pancreatic islets
Patch-clamp characterisation of somatostatin-secreting δ-cells in intact mouse pancreatic islets
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DOI：
10.1111/j.1469-7793.2000.00497.x
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发表时间：
2000-11-01
影响因子：
5.5
通讯作者：
Rorsman, P
中科院分区：
文献类型：
--
作者：
Göpel, SO;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小鼠胰岛的表面细胞.观察到三种类型的电活动对应于α-、β-和δ-细胞。δ细胞在葡萄糖存在下是电活性的，但缺乏在β细胞中看到的振荡模式。相比之下，α细胞在高浓度葡萄糖下是电沉默的，但通过去除糖可以引起动作电位。α-和β-细胞都含有瞬时电压激活的K+电流。在δ-细胞中，K+电流在高于-20 mV时激活，并且被TEA（20 mM）完全阻断。α-细胞与δ-细胞的不同之处在于具有在-40 mV时已经激活的TEA抗性K+电流。免疫细胞化学显示β细胞中存在Kv3.4通道，α细胞中存在TEA抗性Kv4.3通道。因此，瞬时TEA电阻电流的存在可以用于在功能上分离δ细胞和α细胞。在超过-30 mV的去极化期间，在δ细胞中产生TX敏感性Na+电流，并达到350 pA的峰值幅度。该电流的稳态失活在-28 mV时为最大值的一半。δ-细胞还配备有持续的Ca 2+电流，当在2.6mM细胞外Ca 2+下测量时，其在高于-30mV激活并达到60 pA的峰值。在暴露于无葡萄糖培养基的δ细胞中观察到甲苯磺丁脲敏感的K-ATP通道电导。甲苯磺丁脲（0.1mM）的加入使δ细胞去极化并诱发电活动.我们提出，δ细胞中的K-ATP通道与β细胞中的K-ATP通道具有相同的功能，并且将血糖浓度的升高与激素释放的刺激偶联。
1. perforated patch whole-cell configuration of the patch-clamp technique was applied to superficial cells in intact mouse pancreatic islets.2. Three types of electrical activity were observed corresponding to alpha-, beta- and delta -cells. The delta -cells were electrically active in the presence of glucose but lacked the oscillatory pattern seen in the beta -cells. By contrast, the alpha -cells were electrically silent at high glucose concentrations but action potentials could be elicited by removal of the sugar.3. Both alpha- and beta -cells contained transient voltage-activated K+ currents. In the delta -cells, the K+ currents activated above -20 mV and were completely blocked by TEA (20 mM). The alpha -cells differed from the delta -cells in possessing a TEA-resistant K+ current activating already at -40 mV.4. Immunocytochemistry revealed the presence of Kv3.4 channels in beta -cells and TEA-resistant Kv4.3 channels in alpha -cells. Thus the presence of a transient TEA-resistant current can be used to functionally separate the delta- and alpha -cells.5. TX-sensitive Na+ current developed in delta -cells during depolarisations beyond -30 mV and reached a peak amplitude of 350 pA. Steady-state inactivation of this current was half-maximal at -28 mV. The delta -cells were also equipped with a sustained Ca2+ current that activated above -30mV and reached a peak of 60 pA when measrured at 2.6mM extracellular Ca2+.6. A tolbutamide-sensitive K-ATP channel conductance was observed in delta -cells exposed to glucose-free medium. Addition of tolbutamide (0.1 mM) depolarised the delta -cell and evoked electrical activity. We propose that the K-ATP channels in delta -cells serve the same function as in the p-cell and couple an elevation of the blood glucose concentration to stimulation of hormone release.