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Evidence for a P O2 ‐sensitive K + channel in the type‐I cell of the rabbit carotid body
Author(s) -
Delpiano M.A.,
Hescheler J.
Publication year - 1989
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 - 10.1016/0014-5793(89)80623-4
Subject(s) - carotid body , depolarization , conductance , biophysics , patch clamp , chemistry , extracellular , membrane potential , electrophysiology , reversal potential , voltage clamp , analytical chemistry (journal) , medicine , biology , biochemistry , physics , chromatography , receptor , condensed matter physics
Type‐I cells of rabbit carotid bodies were studied with the patch‐clamp technique in the whole‐cell and on the cell‐attached configuration. Cells exhibiting resting potentials of about −40 mV under normoxic conditions ( P O2 : 20 kPa), depolarized during hypoxia ( P O2 : 3.7 kPa). Hypoxia did not affect inward Ca 2+ currents but inactivated outward K + currents in voltage‐clamp experiments. Single‐channel currents recorded for the cell‐attached mode showed a slope conductance of about 137 pS and a 0 mV reversal potential under symmetrical K + concentration (140 mM). The open‐probability ( P o ) of the single channel was dependent on the extracellular P O2 . These data demonstrate the existence of a P O2 ‐sensitive K + channel in type‐I cells, which may account for cell depolarization and the resulting chemosensory response.