Glucose-induced [Ca2+]i oscillations in single human pancreatic islets.
Glucose-induced [Ca2+]i oscillations in single human pancreatic islets.
复制标题
单个人胰岛中葡萄糖诱导的 [Ca2]i 振荡。
作者：
F. Martín;B. Soria
用Fura-2荧光成像技术研究了人胰岛细胞内游离钙浓度([Ca~(2+)]i)随刺激葡萄糖浓度的变化。当葡萄糖浓度从3 mM增加到11 mM时，人胰岛细胞出现三相反应：初始下降(第一相)、快速而短暂的升高(第二相)和频率为1+/-0.3min-1的周期性振荡(第三相)。当葡萄糖浓度从11 mM增加到16.7 mM时，葡萄糖引起的[Ca~(2+)]i振荡频率降低到0.15+/-0.2min~(-1)，幅度不变。人胰岛对刺激葡萄糖浓度的反应在整个胰岛是同步的。新分离的人胰岛对甲苯丁胺(50微米)的反应是[Ca~(2+)]i升高。在100微米二氮卓存在下，葡萄糖浓度从3 mM增加到16 mM时，人的胰岛对葡萄糖的反应是有规律的[Ca~(2+)]i振荡，这种振荡在整个胰岛是同步的，其持续时间受葡萄糖的调节。
Changes in cytosolic free calcium concentrations ([Ca2+]i) in response to stimulatory glucose concentrations were investigated in human pancreatic islets, using Fura-2 fluorescence imaging. Increasing glucose concentration from 3 to 11 mM caused a triphasic [Ca2+]i response in human islets: an initial decrease (phase 1), a rapid and transient increase (phase 2) and periodic oscillations with a frequency of 1 +/- 0.3 min-1 (phase 3). Raising the glucose concentration from 11 to 16.7 mM lowered the frequency of the glucose-induced [Ca2+]i oscillations to 0.15 +/- 0.2 min-1, without changes in their amplitude. Human islet [Ca2+]i response to stimulatory glucose concentrations is synchronous throughout the islet. Freshly isolated human islets responded to tolbutamide (50 microM) with a rise in [Ca2+]i. An increase in glucose concentration, from 3 to 16 mM, in the presence of 100 microM diazoxide, produced a decrease in [Ca2+]i. It is concluded that human islets respond to glucose with regular [Ca2+]i oscillations that are synchronous throughout the islet and whose duration is modulated by glucose.