The effect of denervation on the distribution of the polymorphic forms of troponin components in fast and slow muscles of the adult rat

Abstract

In the soleus muscle of the normal rat the number of cells containing fast troponin I decreased and those containing slow troponin I increased after birth until less than 10% stained for the fast form in the adult muscle. On denervation of soleus muscle this pattern of change was reversed with the result that the majority of cells stained for fast troponin I. The change was more rapid when denervation was carried out at 12 weeks rather than at 52 weeks of age. Denervation of extensor digitorum longus and tibialis anterior muscles produced little change in the distribution of fast and slow troponin I over a period of 12 weeks. After long periods (>24 weeks) of denervation of these fast muscles, fast troponin I was observed in cells in which originally only slow troponin I could be detected. Similar results to those obtained with troponin I in both fast and slow muscles were obtained using antibodies to the fast and slow forms of troponin C and troponin T.