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Lactate/H + transport in skeletal muscle from spinal‐cord‐injured patients
Author(s) -
Pilegaard H.,
Mohr T.,
Kjaer M.,
Juel C.
Publication year - 1998
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/j.1600-0838.1998.tb00175.x
Subject(s) - vastus lateralis muscle , medicine , spinal cord injury , skeletal muscle , spinal cord , psychiatry
In order to evaluate the effect of prolonged muscle inactivity on sarcolemmal lactate/H + transport in humans, the lactate/H + transport capacity was determined in the thigh muscle of spinal‐cord‐injured (SCI) individuals. The lactate transport rate was measured in sarcolemmal giant vesicles produced by collagenase treatment of muscle biopsies obtained from the vastus lateralis muscle. Six SCI subjects with total loss of motor and sensory functions of their lower limbs participated in the study. The duration of the injury ranged from 2 to 15 years. The total lactate transport rate in the muscle of SCI patients was 46.5±2.6 pmol · cm −2 · s −1 (mean±SEM), which corresponds to a 17% lower (P<0.05) transport rate than that found in healthy, untrained subjects. The estimated carriermediated lactate/H + transport capacity was approximately 26% lower in the SCI patients than in healthy, untrained subjects. The observed muscle lactate/H + transport capacity of SCI individuals is in accordance with a positive correlation between the capacity of the lactate/H + transporters and the percentage occurrence of slow‐twitch fibres in a muscle, although there seems to be a wide range of transport capacities within each fibre type. The present results show that the sarcolemmal lactate/H + transport capacity is lower in SCI individuals than in normally physically active subjects, which indicates that prolonged muscle inactivity reduces the lactate/H + transport capacity of human muscle.