人骨格筋の電気生理学的ならびに組織学的研究 第3編 人骨格筋の活動電位の伝導速度について

The conduction velocity of action potential of isolated human skeletal muscle was examined in oxygenated Tyrode's solution. 1. The velocity is distributed mainly between 3 and 4 m/sec, being neither more than 4.5 m/sec, nor less than 2.3 m/sec. 2. In the pectoralis major muscle and the rectus abdominis the conduction velocity does not distribute uniformly, but has two peaks. One peak is between 3 and 3.6 m/sec, and the other is between 3.6 and 4.2 m/sec. 3. When current I is applied intracellulary across the fiber membrane, the membrane potential is changed as much as V in terminal value. Then muscle fibers can be divided into two groups by V/I value and the conduction velocity. In one group V/I is in inverse proportion to the 3 power of the velocity. This means, if resistance of membrane and capacitance of membrane are constant in a group, the conduction velocity is in the proportion to the root of the fiber diameter, which is rational to the cable theory. The difference of two groups may depend upon the difference of capacitance of membrane.