FAST-TO-SLOW MUSCLE CONVERSION BY CHRONIC ELECTROSTIMULATION - EFFECTS ON MITOCHONDRIAL RESPIRATORY-CHAIN FUNCTION WITH POSSIBLE IMPLICATIONS FOR THE GRACILIS NEOSPHINCTER PROCEDURE

The effects of chronic, around the clock, low-frequency electrostimula tion on the respiratory chain activity and cytochrome content of fresh ly isolated mitochondria were evaluated in rabbit skeletal muscle befo re and after 30 days of continuous or cyclical electrostimulation usin g a totally implantable system and a training programme now used in hu mans. The respiratory activity measured in state III increased strongl y after electrostimulation. The efficiency of the respiratory chain in creased significantly after electrostimulation but the activity of com plex I (reduced nicotinamide adenine dinucleotide dehydrogenase) did n ot increase. The amount of cytochromes a and a(3), b(562), and c and c (1) increased clearly after electrostimulation. The respiratory activi ty rate of mitochondria obtained after continuous electrostimulation w as apparently higher than after cyclical electrostimulation. Chronic u ninterrupted low-frequency electrostimulation, using a clinical traini ng programme, induces an increase in mitochondrial respiratory chain a ctivity in purified mitochondria of skeletal muscle. These changes are the basis of induced resistance to fatigue in fast-to-slow muscle con version by chronic electrostimulation.