ACTION POTENTIALS ACCOMPANYING THE CONTRACTILE PROCESS IN SKELETAL MUSCLE

Publisher Website
Google Scholar
Abstract
Action potentials of skeletal muscle as usually recorded from "monophasic" leads are not strictly monophasic, a 2nd phase of varying amplitude being recorded at the killed end, presumably because the lead here is from a demarkation potential gradient which changes with activity, as in nerve. Various technical procedures are described for obtaining a virtually monophasic record. Such a record shows an initial maximum of potential, followed by a prolonged falling phase lasting throughout the period of tension development. Diphasic records may show a wave resembling the T-wave of the heart, due to the summation of 2 long-lasting waves ending at different times at the 2 electrodes. The possibility is considered that the monophasic electromyogram consists of the summation of 2 effects, one associated with a nerve-like conductile mechanism of skeletal muscle and the other associated with the process of tension development. The action potential appears to be independent of initial tension within physiological limits, but the later portion varies with the ability of the muscle to develop tension, as other conditions are altered.

This publication has 2 references indexed in Scilit: