Na channels and two types of Ca channels in rat pancreatic B cells identified with the reverse hemolytic plaque assay.
Na channels and two types of Ca channels in rat pancreatic B cells identified with the reverse hemolytic plaque assay.
复制标题
大鼠胰腺B细胞中的Na通道和两种类型的Ca通道用反向溶血斑块测定法鉴定出来。
DOI：
10.1085/jgp.91.5.617
复制
发表时间：
1988-05
期刊：
影响因子：
--
通讯作者：
Matteson DR
中科院分区：
文献类型：
--
作者：
Hiriart M;Matteson DR
采用反向溶血斑块法（RHPA）研究大鼠胰腺B细胞的分泌特性，并为膜片钳实验鉴定胰岛素分泌细胞。在使用RHPA的分泌研究中，我们发现随着葡萄糖浓度从0提高到20 mM，分泌B细胞的百分比和每个B细胞分泌的胰岛素量增加。使用膜片钳技术的全细胞变异，我们发现鉴定的B细胞有三种能够向内携带电流的通道：(a)河豚毒素敏感、电压依赖性的Na通道，在-40 mV时几乎完全失活，(b)快速失活（FD） Ca通道，(c)缓慢失活（SD） Ca通道。我们已经证明Na通道对B细胞具有重要的功能，因为河豚毒素部分抑制葡萄糖诱导的胰岛素分泌。FD和SD Ca通道的特性在几个方面有所不同。FD通道在-80 mV时失活，时间常数为129微秒，在+15 mV时半最大激活，在100 ms时不失活，它们对Ba2+的传导优于Ca2+，并且在细胞内透析时对冲洗非常敏感。另一方面，SD通道的失活时间常数为2.8 ms，在-5 mV附近达到半最大激活，失活速度快，对Ba2+和Ca2+的传导同样良好，并且对冲刷不敏感。
The reverse hemolytic plaque assay (RHPA) was used to study the secretory properties of single rat pancreatic B cells, and to identify insulin-secreting cells for patch-clamp experiments. In secretion studies using the RHPA, we find that the percentage of secreting B cells and the amount of insulin secreted per B cell increase as the glucose concentration is raised from 0 to 20 mM. Using the whole-cell variation of the patch-clamp technique, we find that identified B cells have three types of channels capable of carrying inward current: (a) tetrodotoxin-sensitive, voltage-dependent Na channels, which are nearly completely inactivated at -40 mV, (b) fast deactivating (FD) Ca channels, and (c) slowly deactivating (SD) Ca channels. We have shown that Na channels are functionally significant to the B cell, because tetrodotoxin partially inhibits glucose-induced insulin secretion. The properties of FD and SD Ca channels differ in several respects. FD channels deactivate at -80 mV, with a time constant of 129 microseconds, they are half-maximally activated near +15 mV, they do not inactivate during 100 ms, they conduct Ba2+ better than Ca2+, and they are very sensitive to washout during intracellular dialysis. SD channels, on the other hand, deactivate with a time constant of 2.8 ms, they are half-maximally activated near -5 mV, they inactivate rapidly, they conduct Ba2+ and Ca2+ equally well, and they are insensitive to washout.