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Potassium currents underlying the oscillatory response in hair cells of the goldfish sacculus.
Author(s) -
Sugihara I,
Furukawa T
Publication year - 1995
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1995.sp021064
Subject(s) - potassium , biophysics , outer hair cells , chemistry , anatomy , biology , inner ear , organic chemistry
1. Ionic currents underlying the oscillatory response of membrane potential were studied in oscillatory‐type hair cells isolated from the goldfish sacculus with the whole‐cell recording method using a patch pipette. 2. Bath application of 4‐aminopyridine (4‐AP; 10 mM) reversibly produced moderate depolarization of the resting potential along with complete suppression of the oscillatory response. Sustained injection of a small depolarizing current also suppressed the oscillatory response. 3. A 4‐AP‐sensitive atypical A‐type K+ current which had a high threshold voltage for inactivation (IA(H)) was found to be a major outward current underlying the oscillatory response. 4. IA(H) was activated with a time constant of 0.4‐10 ms and was inactivated slowly with a time constant of 0.6‐2 s. IA(H) activation and inactivation occurred mostly at membrane potentials more positive than ‐70 mV. 5. There was a clear correlation between activation speed of IA(H) and the frequency of pulse‐evoked oscillation. A ‘hump’‐type response was produced in about one‐quarter of the oscillatory‐type hair cells.