The effect of denervation on selected biochemical properties of skeletal muscle surface membranes was studied. Studies were performed on muscle denervated 1, 2, 3, 5, or 7 days. After denervation the surface membranes of skeletal muscle underwent specific biochemical alterations without gross changes in membrane polypeptide or lipid composition. Seven days after denervation sarcolemmal membranes underwent a slight density shift. Na+,K+(Mg2+)-ATPase activity and sialic acid content increased beginning 3 days postdenervation. Basal, sodium fluoride-stimulated, and isoproterenolstimulated adenyl cyclase activity decreased 50% after 5 days of denervation. Isoproterenol-stimulated activity was enhanced by 5′-guanylyl imidodiphosphate [Gpp (NH) p]. Membrane tentatively identified as transverse tubule increased in yield as denervation progressed. In this fraction endogenous protein kinase activity for a 28,000-MW polypeptide decreased by 50% between days 2 and 3. The decrease in membrane protein phosphorylation was paralleled by a decrease in content of the 28,000-MW polypeptide. These membrane changes may help contribute to our understanding of the physiological alterations observed in skeletal muscles after denervation.
ASJC Scopus subject areas
- Developmental Neuroscience