title: Aging-associated down-regulation of ClC-1 expression in skeletal muscle: phenotypic-independent relation to the decrease of chloride conductance.
abstract: In order to clarify the mechanism underlying the reduction of resting membrane chloride conductance (gCl) 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 gCl 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 gCl and ClC-1 mRNA expression as compared to adult rats. A linear correlation exists between individual values of ClC-1 mRNA and gCl. These results provide evidence that ClC-1 is the main determinant of sarcolemmal gCl and demonstrate that the decrease of gCl observed during aging is associated with a down-regulation of ClC-1 expression in muscle.
authors.affiliation: Department of Pharmacobiology, Faculty of Pharmacy, University of Bari, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Pierno
authors.forename: A
authors.initials: A
authors.lastname: De Luca
authors.forename: C L
authors.initials: CL
authors.lastname: Beck
authors.forename: A L
authors.initials: AL
authors.lastname: George
authors.forename: D
authors.initials: D
authors.lastname: Conte Camerino
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D018118:Chloride Channels / Q000235:genetics*; D002712:Chlorides / Q000378:metabolism / Q000502:physiology; D015536:Down-Regulation; D006801:Humans; D018485:Muscle Fibers, Skeletal / Q000378:metabolism; D009124:Muscle Proteins / Q000235:genetics*; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000502:physiology; D010641:Phenotype; D011506:Proteins / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
chemical_list: C086321:CLC-1 channel; D018118:Chloride Channels; D002712:Chlorides; D009124:Muscle Proteins; D011506:Proteins; D012313:RNA