Goldberg G, Lass Y
J Physiol. 1983 Oct;343:429-37. doi: 10.1113/jphysiol.1983.sp014901.
Acetylcholine (ACh)-induced membrane currents were recorded in voltage-clamped myoballs in culture. The ACh sensitivity and the charge transfer per channel (Qc) were doubled in NH4+ at normal extracellular pH (pHo). Immediately after wash-out of NH4+, the ACh sensitivity and Qc undershot below the control. The recovery period of the ACh sensitivity and Qc was about 20 min. The ACh sensitivity and Qc greatly increased at alkaline pHo and decreased at acid pHo. We suggest that the intracellular H+ ions can block the ACh-induced channel. The pHo effects may be mediated by a similar (but smaller) change in the intracellular pH (pHi). Intracellular alkalinization can improve the channel function.
在培养的电压钳制肌球中记录乙酰胆碱(ACh)诱导的膜电流。在正常细胞外pH(pHo)条件下,NH4+使ACh敏感性和每个通道的电荷转移量(Qc)增加一倍。NH4+洗脱后立即出现ACh敏感性和Qc低于对照的情况。ACh敏感性和Qc的恢复期约为20分钟。在碱性pHo时ACh敏感性和Qc大大增加,在酸性pHo时降低。我们认为细胞内H+离子可阻断ACh诱导的通道。pHo效应可能由细胞内pH(pHi)的类似(但较小)变化介导。细胞内碱化可改善通道功能。