Mozhaeva G N, Naumova A P, Khodorov B I
Neirofiziologiia. 1983;15(5):495-503.
Ionic currents through batrachotoxin-modified sodium channels in frog nerve fibres were measured over a wide range of membrane potentials. At potentials above +80 mV currents decay in time and their steady-state level decreased as potentials increased. "Instantaneous" current measurements have shown that this phenomenon was due to the decrease in net channel conductance. Scorpion toxin affected current kinetics only slightly at these potentials, which suggested that these decays were not caused by usual inactivation process. Externally applied procaine induced slow (tens of ms) potential-dependent block of batrachotoxin-modified channels at large positive potentials. At large negative potentials (above -100 mV) "instantaneus" currents decreased due to fast voltage-dependent block of the channels by calcium ions.
在很宽的膜电位范围内测量了蛙神经纤维中经蟾毒素修饰的钠通道的离子电流。在高于 +80 mV 的电位下，电流随时间衰减，其稳态水平随电位升高而降低。“瞬时”电流测量表明，这种现象是由于通道净电导降低所致。在这些电位下，蝎毒素对电流动力学的影响很小，这表明这些衰减不是由通常的失活过程引起的。在大的正电位下，外部施加的普鲁卡因会诱导经蟾毒素修饰的通道出现缓慢（数十毫秒）的电位依赖性阻断。在大的负电位（高于 -100 mV）下，“瞬时”电流由于钙离子对通道的快速电压依赖性阻断而降低。
