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Osmosensitivity of an inwardly rectifying chloride current revealed by whole‐cell and perforated‐patch recordings in cultured rat cortical astrocytes
Author(s) -
Fava Marianna,
Ferroni Stefano,
Nobile Mario
Publication year - 2001
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(01)02221-9
Subject(s) - intracellular , extracellular , tonicity , cytoplasm , osmoregulation , hypertonic saline , astrocyte , biophysics , endocrinology , chemistry , medicine , osmotic concentration , biology , microbiology and biotechnology , neuroscience , central nervous system , ecology , salinity
The osmosensitivity of the inwardly rectifying Cl − current ( I Clh ), expressed by primary cultured rat neocortical astrocytes long‐term treated with dibutyryl cyclic AMP, was investigated in the whole‐cell and perforated‐patch modes. In whole‐cell experiments, whereas hypotonic extracellular solution ( Δ =100 mOsmol) did not cause any change in I Clh , hypertonicity produced a slowly developing, ∼40% reversible decrease in current magnitude. By contrast, in perforated‐patch experiments, exposure to a less hypertonic saline ( Δ =50 mOsmol) depressed the current to ∼50%, and hypotonicity induced a ∼50% slow increase in I Clh . These differences in osmosensitivity between the two experimental modes suggest that the osmoregulation of I Clh may be mediated by complex intracellular mechanism(s), which appear(s) to be partly compromised by the dialysis of the astrocytic cytoplasm.