Byerly L, Meech R, Moody W
J Physiol. 1984 Jun;351:199-216. doi: 10.1113/jphysiol.1984.sp015241.
Cells from the circumoesophageal nerve ring of the pond snail Lymnaea stagnalis were internally perfused with solutions containing Cs aspartate, EGTA and pH buffers. Time-dependent, voltage-dependent 'residual' outward currents were observed at positive potentials. They were found to be carried largely by H+. The outward H+ currents were reduced by high internal pH, low external pH, external Cd2+ and 4-aminopyridine. External tetraethylammonium ions reduced the H+ currents but had a more effective blocking action on the K+ currents in these cells. All five agents reduced the maximum H+ conductance. In addition Cd2+, low external pH and high internal pH were found to shift the voltage dependence of the H+ current to more positive potentials. There was no significant difference between H+ currents recorded with the internal pCa2+ about 7 and those recorded with the internal pCa2+ near 5. It is likely that the H+ channel described here provides the basis for the increase in H+ permeability described by Thomas & Meech (1982) in depolarized Helix neurones. As judged by their sensitivity to different antagonists, H+ channels are unlike any other previously described channel. They are highly selective for protons and we suggest that their role in molluscan neurones is to compensate for the rapid intracellular acidification which is generated by trains of action potentials (Ahmed & Connor, 1980).
用含有天冬氨酸铯、乙二醇双四乙酸（EGTA）和pH缓冲液的溶液对椎实螺（Lymnaea stagnalis）食管周围神经环的细胞进行内部灌注。在正电位下观察到了随时间和电压变化的“残余”外向电流。发现这些电流主要由H⁺携带。高细胞内pH、低细胞外pH、细胞外Cd²⁺和4-氨基吡啶可降低外向H⁺电流。细胞外四乙铵离子可降低H⁺电流，但对这些细胞中的K⁺电流具有更有效的阻断作用。所有这五种试剂均降低了最大H⁺电导。此外，发现Cd²⁺、低细胞外pH和高细胞内pH可使H⁺电流的电压依赖性向更正的电位移动。细胞内pCa²⁺约为7时记录的H⁺电流与细胞内pCa²⁺接近5时记录的H⁺电流之间无显著差异。此处描述的H⁺通道可能为Thomas和Meech（1982年）在去极化的蛞蝓神经元中描述的H⁺通透性增加提供了基础。根据它们对不同拮抗剂的敏感性判断，H⁺通道不同于以往描述的任何其他通道。它们对质子具有高度选择性，我们认为它们在软体动物神经元中的作用是补偿由一连串动作电位产生的快速细胞内酸化（Ahmed和Connor，1980年）。
