SPONTANEOUS fibrillation potentials occurring in skeletal muscle after surgical denervation are one of the classical signs of denervation sensitization. At present, no satisfactory explanation is available for the occurrence of this pathological change. Several theories in the past have pointed to the possible role of the neurotransmitter and/or nerve impulse activity as being essential for physiological maintenance of muscle. The effect of a prolonged and reversible simple nerve impulse deprivation on the electromyographic potentials of the skeletal muscle has not been reported, prior to a preliminary report by the present authors.1In this study, a continuous conduction block of the sciatic nerve of the rabbit was maintained for eight days, with a silicone polymer-lidocaine implant. This resulted in sustained absence of nerve impulses and corresponding limb paralysis. Shortly after removal of this reversible block, essentially normal sensory and motor functions returned. The electrophysiological findings of these muscles form