Differential effects of disuse preceding denervation on the onset and development of fibrillation in fast and slow muscles.

Section of the sciatic nerve, performed after a week of muscular disuse, is followed by fibrillation earlier in the soleus (S) than in the anterior tibialis (AT) muscle of the rat. The subsequent development of fibrillation, which is different in the control denervated S as compared with the control denervated AT, tends to become similar in the disused-denervated muscles.