| Abstract: | The origin of the membrane changes induced in skeletal muscle by denervation has been investigated by examining partially denervated rat hindlimb muscles rendered inactive for 2-3 days by a chronic conduction block in the sciatic nerve. Extra-junctional sensitivity to acetylcholine and spike resistance to tetrodotoxin developed to the same extent in the denervated and the adjacent innervated but inactive fibres. On the other hand, impulse-blocked fibres of control muscles not containing denervated fibres showed, at this early time, little membrane changes. These results are interpreted as indicating that the response of muscle to denervation is due to the combined action of inactivity and products of nerve degeneration. |
