BIOCHEMICAL CHARACTERISTICS OF DENERVATED SKELETAL MUSCLE, AT REST AND AFTER DIRECT STIMULATION

Abstract

14 days after denervation, at a time when significant atrophy had developed, the gastrocnemius muscle of the rat exhibited low levels of glycogen, creatine phosphate and adenosine triphosphate. Lactic acid, inorganic phosphate, hexose monophosphate, hexose diphosphate and total acid soluble phosphate were normal. After a similar period of denervation detns. of phosphorylation, glycolysis, in vitro O2 consumption, suc-cino-oxidase and dehydrogenase activities indicated that the transfer of H2 from substrate to molecular 0% in the denervated muscle proceeds through the normal pathways, and at a rate which is adequate for normal respiration. Glycogen breakdown and resynthesis was normal at 11/2 to 2 days after denervation, before fibrillation had begun. After the onset of fibrillation there is a drop in the initial glycogen level and impairment in the ability of the muscle to restore its glycogen after contraction. Similar but somewhat delayed effects were observed as regards creatine phosphate.