In order to clarify the mechanism underlying the reduction of resting membrane chloride conductance (g(Cl)) during aging, the levels of mRNA encoding the principal skeletal muscle chloride channel, ClC-1, were measured. Total RNA samples isolated from tibialis anterior muscles of aged (24-29 months old) and adult (3-4 months old) rats were examined for ClC-1 expression using Northern blot analysis, and macroscopic g(Cl) was recorded from extensor digitorum longus muscle fibers from each adult and aged rat in vitro using a two intracellular microelectrode technique. Although interindividual variability was observed, aged rats exhibited a parallel reduction of both g(Cl) and ClC-1 mRNA expression as compared to adult rats. A linear correlation exists between individual values of ClC-1 mRNA and g(Cl). These results provide evidence that ClC-1 is the main determinant of sarcolemmal g(Cl) and demonstrate that the decrease of g(Cl) observed during aging is associated with a down-regulation of ClC-1 expression in muscle.

Aging-associated down-regulation of CLC-1 expression in skeletal muscle: phenotypic-independent relation to the decrease of chloride conductance

PIERNO, Sabata;DE LUCA, Annamaria;CONTE, Diana
1999-01-01

Abstract

In order to clarify the mechanism underlying the reduction of resting membrane chloride conductance (g(Cl)) during aging, the levels of mRNA encoding the principal skeletal muscle chloride channel, ClC-1, were measured. Total RNA samples isolated from tibialis anterior muscles of aged (24-29 months old) and adult (3-4 months old) rats were examined for ClC-1 expression using Northern blot analysis, and macroscopic g(Cl) was recorded from extensor digitorum longus muscle fibers from each adult and aged rat in vitro using a two intracellular microelectrode technique. Although interindividual variability was observed, aged rats exhibited a parallel reduction of both g(Cl) and ClC-1 mRNA expression as compared to adult rats. A linear correlation exists between individual values of ClC-1 mRNA and g(Cl). These results provide evidence that ClC-1 is the main determinant of sarcolemmal g(Cl) and demonstrate that the decrease of g(Cl) observed during aging is associated with a down-regulation of ClC-1 expression in muscle.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11586/112645
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