[Changes in concentrations of nerve- and muscle-related proteins during reinnervation of slow and fast muscles]

The concentration of the nerve-related (gamma-enolase) and muscle-related (beta-enolase and creatine kinase of B type) proteins was measured in the rat sciatic nerve and the muscles; soleus (SOL), a typical slow-twitch muscle, and extensor digitorum longus (EDL), a typical fast-twitch muscle. The nerves and muscles were subjected to experimental manipulation of their innervation. 1. Nerve-related protein, gamma-enolase. The concentration of gamma-enolase in the distal part of the transected sciatic nerve was decreased in 2 weeks to about 10% of normal. When the sciatic nerve was sutured immediately after the transection, the concentration of gamma-enolase recovered in 34 weeks to a level of about 62.8% of normal. 2. Fast muscle-related protein, beta-enolase. The concentration of the beta-enolase in the SOL and the EDL was reduced after sciatic nerve transection. When the sciatic nerve was sutured immediately after complete transection, the concentration of beta-enolase of SOL and EDL became almost equal on the 34th week. After cross union of the nerves innervating the SOL and EDL muscles, the concentration of the beta-enolase were almost equal on the 20th post-operative week in the both muscles, and reversed on the 34th week. The beta-enolase concentrations in the SOL and EDL muscles innervated by the TTX-perfused sciatic nerve were reduced to 72.3% and 70.4%, respectively. Continuous electrical stimulation of the sciatic nerve reduced the beta-enolase concentration in the EDL to 51.8% of normal, but did not affect the SOL significantly. 3. Slow muscle-related protein, creatine kinase of B type (CK-B). After complete severance of the sciatic nerve the CK-B concentration showed a marked increase in the both muscles. When the sciatic nerve was sutured immediately after transection, the CK-B concentration on the 34th week was about 35.3% in the SOL and close to normal in the EDL. On the 34th week after cross union of the nerves innervating the SOL and EDL muscles, the CK-B concentration was reduced to about 41.1% in the SOL, while it was increased to about 111% in the EDL. On the 20th week after self re-union of the nerves innervating the SOL and EDL muscles, the CK-B concentration in the EDL recovered the normal level, but in the SOL muscle it was increased significantly. 4. It appears that the measurement of the concentration of gamma-enolase, beta-enolase and CK-B can provide valuable informations on the recovery course of skeletal muscles after nerve injury.