title: Chronic electrical stimulation of nongrafted and grafted skeletal muscles in rats.
abstract: Our purpose was to determine the effects of chronic electrical stimulation on the structure and function of neve-intact grafts in rats. Fourteen days after grafting, extensor digitorum longus (EDL) grafts (n = 6) and nongrafted EDL muscles (n = 4) were stimulated 8 h/day at 10 Hz for 26 days. Measurements were made subsequently of cytochrome c concentration, capillary density, contraction and relaxation times, developed tension, and the resistance to fatigue. Compared with contralateral nonstimulated grafts, chronically stimulated grafts demonstrated a 65% greater cytochrome c concentration, 45% greater number of capillaries per millimeter squared, 30% greater resistance to fatigue, 35% longer contraction time, 30% longer relaxation time, and 30% lower maximum tetanic tension. The differences that resulted from the stimulation of nongrafted EDL muscles were significant but of less magnitude. Chronic stimulation of 8 h/day provided a mixed stimulus for adaptation that enhanced the metabolic and endurance characteristics of fibers in muscles and grafts, but decreased the total fiber cross-sectional area and development of force.
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D002196:Capillaries; D003574:Cytochrome c Group / Q000378:metabolism; D004558:Electric Stimulation; D005260:Female; D009119:Muscle Contraction; D009132:Muscles / Q000098:blood supply / Q000378:metabolism / Q000502:physiology* / Q000637:transplantation; D051381:Rats; D011919:Rats, Inbred Strains; D012038:Regeneration
chemical_list: D003574:Cytochrome c Group