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The Na+‐dependent regulation of the internal pH in chick skeletal muscle cells. The role of the Na+/H+ exchange system and its dependence on internal pH.
Author(s) -
Vigne P.,
Frelin C.,
Lazdunski M.
Publication year - 1984
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1984.tb02060.x
Subject(s) - biology , skeletal muscle , microbiology and biotechnology , biophysics , sodium–hydrogen antiporter , sodium , anatomy , chemistry , organic chemistry
The internal pH (pHi) of chick muscle cells is determined by the transmembrane Na+ gradient. Li+, but not K+, Rb+ or Cs+, can substitute for Na+ for regulating the internal pH of chick muscle cells. Pharmacological evidence using amiloride and amiloride analogs has shown that the Na+/H+ exchange system is the membrane mechanism that couples the pHi to the transmembrane Na+ gradient. The pHi dependence of the amiloride‐sensitive Na+/H+ exchange mechanism was defined. Internal H+ interacts cooperatively with the Na+/H+ exchange system, in contrast with external H+, thus indicating an asymmetrical behaviour of this exchanger. The half‐maximum effect for the activation by the internal H+ of the Na+ transporting activity of the amiloride‐sensitive Na+/H+ exchange was observed at pH 7.4. The Hill coefficient of the H+ concentration dependence is higher than 3. Insulin was shown to have no effect on the pHi of chick muscle cells.