Muscle-specific beta-enolase concentrations after cross- and random innervation of soleus and extensor digitorum...

The concentration of beta-enolase, a highly specific marker of the skeletal muscle of rats, was determined in a slow-twitch muscle, the soleus (SOL) and a fast-twitch muscle, the extensor digitorum longus (EDL) after cross-innervation, random reinnervation, or denervation. The beta-enolase concentration is normally high in EDL and low in SOL. When the nerves entering into these muscles were cross-sutured, the beta-enolase concentration in EDL decreased and that in SOL increased to reach an almost equal value in 20 weeks and by the 35th week the SOL ultimately had a higher beta-enolase concentration than the EDL. When the sciatic nerve trunk was completely transected and sutured immediately, the beta-enolase concentration in EDL decreased and that of SOL increased; in 20 weeks SOL had a beta-enolase concentration similar to that of the EDL. When these muscles were denervated by cutting the sciatic nerve trunk, their beta-enolase concentrations were markedly lowered, but EDL still retained on the 12th week a beta-enolase value comparable to the normal SOL. Possible mechanisms behind the observed changes in beta-enolase concentration are discussed.