ISSN:
1432-1912
Keywords:
Skeletal muscle
;
Chloride channel
;
Postnatal development
;
Aging
;
Pharmacological characterization
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Enantiomers of 2-(p-chlorophenoxy) propionic acid, compounds acting specifically on chloride channels of adult rat skeletal muscles, have been tested on extensor digitorum longus (EDL) muscle of developing and aged rats, in an attempt to characterize the chloride channels responsible for the low chloride conductance (GC1) found in the above physiological situations. The S-(−) enantiomer, which produces a concentration-dependent inhibition of GC1 in the adult EDL, is less effective in inhibiting GC1 of EDL of either 2–3 weeks or 29 months old rats, particularly at low concentrations. The R-(+) isomer, which in the adult enhances GC1 at low concentrations and blocks it at concentrations higher than 10 μM, lacks inhibitory action, enhancing GC1 in both developing and aged EDL. At 30–40 days of age both the enantiomers produce almost the same effects exerted in adulthood. From these data we hypothesize that the low GC1 found in EDL of developing and aged rats might be due not only to a lower number of conductive channels but also to the presence of a mixed population of isoforms of chloride channels having different pharmacological properties.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00168731
