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Ca 2+ ‐dependent K + channels from rat olfactory cilia characterized in planar lipid bilayers
Author(s) -
Castillo Karen,
Bacigalupo Juan,
Wolff Daniel
Publication year - 2005
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/j.febslet.2005.01.079
Subject(s) - charybdotoxin , apamin , cyclic nucleotide gated ion channel , chemistry , biophysics , iberiotoxin , inhibitory postsynaptic potential , channel blocker , potassium channel , membrane potential , biochemistry , biology , cyclic nucleotide , neuroscience , nucleotide , calcium , organic chemistry , gene
Olfactory cilia contain cyclic nucleotide‐gated and Ca 2+ ‐dependent Cl − conductances that underlie excitatory chemotransduction, and a Ca 2+ ‐dependent K + (K Ca ) conductance, apparently involved in inhibitory transduction. Previous single‐channel patch‐clamp studies on olfactory cilia revealed four different K Ca s, with different conductances and kinetics. Here, we further characterized these channels in planar bilayers, where blockers could be properly tested. All four ciliary K Ca s were observed: The 16 pS channel, K 0.5,Ca = 40 μM and apamin‐sensitive; the 30 and 50 pS channel, K 0.5,Ca = 59 μM, clotrimazole‐sensitive and charybdotoxin‐insensitive; the 60 pS channel, clotrimazole‐sensitive and charybdotoxin‐insensitive; and the 210 pS channel, K 0.5,Ca = 63 μM, blocked by charybdotoxin and iberiotoxin. The presence of the 16 and 210 pS channels was confirmed by immunoblotting.