Effects of Electrical Constants on Conduction Velocity of Action Potentials Measured with Unidimensional Latency-topography in Frog Skeletal Muscle Fibers

抄録

1. Conduction velocity (CV) of an action potential recorded from a single muscle fiber of the frog was measured with a new method, unidimensional latency-topography, and electrical membrane constants were determined for the same muscle fiber. CV=1.96±0.27m/sec (n=52) at about 20°C. Temperature coefficient of CV: Q₁₀=2.0. Electrical membrane constants in the same muscle fibers (n=52): λ= 3.25±0.83mm, τ=33.4±14.3msec, C_m=6.09±2.13μF/cm², D=129.4±28.9μm (mean±S.D.).<br>2. The CV decreased linearly with increment of time constant, τ, and membrane capacity per unit area, C_m. The space constant, λ, and the fiber diameter of the muscle fiber, D, did not correlate with CV. It was concluded that the T-system, which contributes largely to membrane capacity, has a great influence on the CV.