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Variation in Large‐Conductance, Calcium‐Activated Potassium Channels from Hair Cells Along the Chicken Basilar Papilla
Author(s) -
Duncan R. K.,
Fuchs P. A.
Publication year - 2003
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.2002.029785
Subject(s) - bk channel , calcium activated potassium channel , biophysics , tonotopy , chemistry , potassium channel , conductance , hair cell , microbiology and biotechnology , protein subunit , electrophysiology , anatomy , biology , biochemistry , neuroscience , inner ear , cochlea , gene , mathematics , combinatorics
The mechanism for electrical tuning in non‐mammalian hair cells rests within the widely diverse kinetics of functionally distinct, large‐conductance potassium channels (BK), thought to result from alternative splicing of the pore‐forming α subunit and variable co‐expression with an accessory β subunit. Inside‐out patches from hair cells along the chicken basilar papilla revealed ‘tonotopic’ gradations in calcium sensitivity and deactivation kinetics. The resonant frequency for the hair cell from which the patch was taken was estimated from deactivation rates, and this frequency reasonably matched that predicted from the originating cell's tonotopic location. The rates of deactivation for native BK channels were much faster than rates reported for cloned chicken BK channels including both α and β subunits. This result was surprising since patches were pulled from hair cells in the apical half of the papilla where β subunits are most highly expressed. Heterogeneity in the properties of native chicken BK channels implies a high degree of molecular variation and hinders our ability to identify those molecular constituents.