Electrical Inexcitability of the Synaptic Membrane in the Frog Skeletal Muscle Fibre

Abstract

VARIOUS types of evidence indicate that the end-plate potential of frog twitch muscle fibres is an electrically inexcitable synaptic activity^1,2. Electrical inexcitability of the synaptic membrane has been demonstrated most clearly in cells in which electrically excitable activity is lacking, for example, the electro-plaques of marine electric fishes³ and slow muscle fibres of frog⁴. Electrical inexcitability of synaptic membranes in other cells has also been demonstrated^1,2. Hitherto, however, it has not been shown that the chemically excitable⁵ synaptic membrane of twitch muscle fibres is also unresponsive to electrical stimuli. The junctional region is small, and there is intermingling of membrane of greater and lesser chemical sensitivity⁵.