Spontaneous electrical activity in muscles of dystrophic (dy/dy) mice

Spontaneous electrical activity of tibialis anterior (TA) muscles was recorded using extracellular electrodes in dystrophic and phenotypically normal mice. Abnormal levels of spontaneous activity were recorded in the muscles of adult dystrophic mice. The activity was reduced by more than 75% after sciatic nerve section in anaesthetised dystrophic mice suggesting that most of the activity was neurally mediated. No abnormal activity was seen in the biceps brachii muscles of adult dystrophic mice. No abnormal spontaneous activity was seen in young (2-3-week-old) dystrophic mice. As degeneration of muscle fibres begins at about 7 days of age in dystrophic hindlimb muscles, the onset of the abnormal spontaneous EMG activity could not be considered causally related to muscle fibre degeneration.