Rae J L
Department of Physiology, Mayo Foundation, Rochester, MN 55905.
Curr Eye Res. 1994 Sep;13(9):679-86. doi: 10.3109/02713689408999904.
Isolated epithelial cells from chick, pig, monkey, rabbit, bovine, and human lenses contain K+ channels that often turn on with a delay after a voltage step and have a larger macroscopic conductance for outward currents than for inward currents even with the same K+ concentration on both sides of the membrane. These outward rectifiers are quite diverse between different lens types and more than one kind can be present even within a single lens species. The channels differ substantially in the voltage dependence of their opening, their deactivation time constants, and the time course of their inactivation. Most produce currents of the delayed rectifier type but others show similarities to A-type currents. Because these different channels open at different voltages, inactivate to different degrees and represent different fractions of the total conductance from one lens cell to another, their contribution to the resting voltage is not the same in all cells investigated. These currents are the most frequently occurring in bovine, pig, monkey, and human lens epithelium and also occur commonly in chick lens epithelium. They occur less frequently in rodents.
从鸡、猪、猴、兔、牛和人晶状体中分离出的上皮细胞含有钾离子通道，这些通道在电压阶跃后通常会延迟开启，并且即使在膜两侧钾离子浓度相同的情况下，外向电流的宏观电导也大于内向电流。这些外向整流器在不同晶状体类型之间差异很大，甚至在单个晶状体物种内也可能存在不止一种类型。这些通道在开启的电压依赖性、失活时间常数以及失活的时间进程方面有很大差异。大多数产生延迟整流器类型的电流，但其他一些与A型电流有相似之处。由于这些不同的通道在不同电压下开启，失活程度不同，并且在一个晶状体细胞与另一个晶状体细胞之间代表总电导的不同部分，因此它们对静息电压的贡献在所有研究的细胞中并不相同。这些电流在牛、猪、猴和人晶状体上皮中最常出现，在鸡晶状体上皮中也普遍存在。它们在啮齿动物中出现的频率较低。
