Kurenny D E, Barnes S
University of Calgary, Faculty of Medicine, Alberta, Canada.
Neurosci Lett. 1994 Apr 11;170(2):225-8. doi: 10.1016/0304-3940(94)90324-7.
The effect of extracellular pH (pHe 6.9-8.1) and intracellular pH (pHi 6.4-8.1) on the non-inactivating voltage-sensitive M-like potassium current (IKx) was studied in patch-clamped salamander rod photoreceptors. The midpoint of the IKx activation curve shifted by 6.6 mV per pHe unit, with acidification producing positive shifts and alkalinization producing negative shifts. The time constant of IKx activation shifted with pHe in a manner consistent with the shifts in the activation curve. Maximum conductance and gating charge were unaffected by changes in pHe. IKx did not depend on pHi. Given the importance of IKx in rod function, these results suggest that pHe could affect the signal transmitted from rods by changing IKx activation parameters.
在膜片钳记录的蝾螈视杆光感受器中，研究了细胞外pH值（pHe 6.9 - 8.1）和细胞内pH值（pHi 6.4 - 8.1）对非失活电压敏感性M型钾电流（IKx）的影响。IKx激活曲线的中点每单位pHe变化6.6 mV，酸化导致正向偏移，碱化导致负向偏移。IKx激活的时间常数随pHe的变化方式与激活曲线的偏移一致。最大电导和门控电荷不受pHe变化的影响。IKx不依赖于pHi。鉴于IKx在视杆功能中的重要性，这些结果表明pHe可能通过改变IKx激活参数来影响从视杆传递的信号。
