Allen C N, Akaike A, Albuquerque E X
J Physiol (Paris). 1984;79(4):338-43.
The patch clamp technique was used to record the currents flowing through single ion channels in isolated frog muscle fibers. The majority of the acetylcholine (ACh)-activated channels had a conductance of 32 pS, although 20 pS channels were also occasionally observed. Lifetimes of ACh-activated channels increased with the transmembrane potential in the range from - 30 mV to - 105 mV. In these same fibers we also observed channels which were activated by low concentrations of batrachotoxin (BTX; 10 nM). These channels, presumed to be Na channels, had a conductance of 19 pS and opened at potentials at which Na channels would not normally open. A notable feature of these BTX-activated channels was that they opened and closed repeatedly. Therefore, it appears that the toxin, in addition to activating Na channels, also blocks the inactivation process. The physiological properties of these channels reveal significant differences between the ion channels of tissue-cultured and mature tissues.
采用膜片钳技术记录分离的蛙肌纤维中单个离子通道的电流。大多数乙酰胆碱（ACh）激活的通道电导为32 pS，不过偶尔也能观察到20 pS的通道。ACh激活通道的寿命在-30 mV至-105 mV范围内随跨膜电位增加。在这些相同的纤维中，我们还观察到由低浓度的蟾毒素（BTX；10 nM）激活的通道。这些通道被推测为钠通道，电导为19 pS，且在钠通道通常不会开放的电位下开放。这些BTX激活通道的一个显著特征是它们会反复开闭。因此，似乎该毒素除了激活钠通道外，还阻断失活过程。这些通道的生理特性揭示了组织培养组织和成熟组织的离子通道之间存在显著差异。
