Biophysical properties of gap junctions between freshly dispersed pairs of mouse pancreatic beta cells.
Biophysical properties of gap junctions between freshly dispersed pairs of mouse pancreatic beta cells.
复制标题
新鲜分散的小鼠胰腺β细胞对之间间隙连接的生物物理特性。
DOI：
10.1016/s0006-3495(91)82200-7
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发表时间：
1991
影响因子：
3.4
通讯作者：
Bennett,MV
中科院分区：
文献类型：
--
作者：
Perez-Armendariz,M;Roy,C;Spray,DC;Bennett,MV
β细胞之间通过间隙连接的偶联被假定为整个胰岛葡萄糖诱导活性的电同步的主要机制。我们的特点是通过两个独立的膜片钳电路的全细胞记录的小鼠胰腺β细胞对之间的连接电导。大多数对是偶联的（67%，n=155），尽管平均连接电导（gj）（215 +/- 110 pS）低于其他组织中报告的值。偶联可以长时间记录，长达40分钟。跨连接膜或非连接膜施加电压对gj没有影响。长达几个小时的治疗，以增加细胞内cAMP水平没有影响gj。电耦合对没有显示染料荧光黄的转移。辛醇（2 mM）可逆地降低gj。较低浓度的辛醇（0.5 mM）和庚醇（0.5 mM）比所需的解偶联β细胞降低电压依赖性K+和Ca 2+电流在非连接膜。虽然在这些实验中记录的gj将预期提供的电流流过只有几个通道的单位电导先前报告的其他间隙连接，没有单位的连接电流，即使在可逆的抑制gj辛醇。这一结果表明，β细胞之间间隙连接通道的单通道电导小于其他组织（小于20 pS），或者小的平均电导是由于打开和关闭状态之间的转换太快或太慢而无法分辨。
Coupling between beta cells through gap junctions has been postulated as a principal mechanism of electrical synchronization of glucose-induced activity throughout the islet of Langerhans. We characterized junctional conductance between isolated pairs of mouse pancreatic beta cells by whole-cell recording with two independent patch-clamp circuits. Most pairs were coupled (67%, n=155), although the mean junctional conductance (gj) (215 +/- 110 pS) was lower than reported in other tissues. Coupling could be recorded for long periods, up to 40min. Voltage imposed across the junctional or nonjunctional membranes had no effect on gj. Up to several hours of treatment to increase intracellular cAMP levels did not affect gj. Electrically coupled pairs did not show transfer of the dye Lucifer yellow. Octanol (2 mM) reversibly decreased gj. Lower concentrations of octanol (0.5 mM) and heptanol (0.5 mM) than required to uncouple beta cells decreased voltage-dependent K+ and Ca2+ currents in nonjunctional membranes. Although gj recorded in these experiments would be expected to be provided by current flowing through only a few channels of the unitary conductance previously reported for other gap junctions, no unitary junctional currents were observed even during reversible suppression of gj by octanol. This result suggests either that the single channel conductance of gap junction channels between beta cells is smaller than in other tissues (less than 20 pS) or that the small mean conductance is due to transitions between open and closed states that are too rapid or too slow to be resolved.