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Chloride efflux measurements in mammalian skeletal muscle
Author(s) -
Hayward B. S.,
Barchi R. L.
Publication year - 1980
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.880030304
Subject(s) - chemistry , efflux , mannitol , chloride , conductance , compartment (ship) , extracellular , flux (metallurgy) , skeletal muscle , sodium , intracellular , biophysics , analytical chemistry (journal) , anatomy , biochemistry , chromatography , biology , oceanography , mathematics , organic chemistry , combinatorics , geology
A rapid sampling technique has been used to resolve the components of 36 Cl efflux from isolated extensor digitorum longus (EDL) muscles of young rats. Four distinct fluxes with apparent rate constants of 4.40 ± 0.02 min −1 (k 1 ), 1.30 ± 0.04 min −1 (k 2 ), 0.24 ± 0.04 min −1 , (k 3 ), and 0.048 ± 0.05 min −1 (k 4 ) at 30°C were identified. Together, these fluxes accounted for the movement of more than 98% of exchangeable muscle chloride (Cl) ions. The muscle compartment associated with the fastest flux (k 1 ) contained 23% ± 2% of the total muscle Cl corresponding to the extracellular space as determined with inulin or mannitol. The compartment associated with k 2 accounted for 71% of the intracellular volume, and k 2 was assumed to represent 36 Cl efflux across the surface membrane. The rate constant k 2 was temperature‐dependent with a Q 10 of 1.11 between 5°C and 30°C. Acromatic carboxylic acids known to block sarcolemmal Cl conductance (G cl ) specifically lowered k 2 by 25% at 30°C, as did replacement of external Cl with nitrate.