Effect of cross innervation on biochemical characteristics of skeletal muscles

Abstract

Cross innervations were performed on the FDL (flexor digitorium longus) and soleus muscles of young cats. Sixty days after the operative procedure it was found that the contraction of the cross-innervated soleus was accelerated whereas that of the cross-innervated FDL was slowed. Changes in the enzyme profiles of the muscles also occurred. Activity levels of the glycolytic enzymes, pyruvic kinase, and aldolase increased in the cross-innervated soleus, but the oxidative enzymes, malic dehydrogenase, and isocitric dehydrogenase decreased. Conversely, pyruvic kinase and aldolase decreased in the cross-innervated FDL, and malic dehydrogenase and isocitric dehydrogenase increased. Cross innervation of fast and slow muscles resulted in changes in these muscles so that the slow muscle resembled a fast muscle in both its contractile response and enzymic profile, whereas the fast muscle resembled the slow in these respects.