Radial propagation of muscle action potential along the tubular system examined by potential-sensitive dyes.
Radial propagation of muscle action potential along the tubular system examined by potential-sensitive dyes.
复制标题
通过电位敏感染料检查肌肉动作电位沿管状系统的径向传播。
DOI：
10.1085/jgp.76.6.751
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发表时间：
1980
期刊：
影响因子：
--
通讯作者：
Gilai,A
中科院分区：
文献类型：
--
作者：
Nakajima,S;Gilai,A
Isolated single (Xenopus) muscle fibers were stained with a non-permeant potential-probing dye, merocyanine rhodanine (WW375) or merocyanine oxazolone (NK2367). When the fiber was massively stimulated, an absorption change (wave a), which seemed to reflect the action potential, occurred. Simultaneous recording of optical changes and intracellular action potentials revealed that the time-course of wave a was slower than the action potential: the peak of wave a was attained at 1 ms, and the peak of action potential was reached at 0.5 ms after the stimulation. This difference suggests that wave a represents the potential changes of the whole tubular membrane and the surface membrane, whereas the action potential represents a surface potential change. This idea was substantiated by recording absorption signals preferentially from the surface membrane by recording the absorption changes at the edge of the fiber. Wave a obtained by this method was as quick as the intracellular action potential. The value of radial conduction velocity of action potential along the T system, calculated by comparing the action potential with wave a, was 6.4 cm/s at 24.5 degrees C, in fair agreement with González-Serratos (1971. J. Physiol. [Lond.]. 212:777-799). The shape of wave a suggests the existence of an access delay (a conduction delay at the orifice of the T system) of 130 microseconds.
