An M-like potassium current in the guinea pig cochlea.
Potassium M currents play a role in stabilizing the resting membrane potential. These currents have previously been identified in several cell types, including sensory receptors. Given that maintaining membrane excitability is important for mechano-electrical transduction in the inner ear, the presence of M currents was investigated in outer hair cells isolated from the guinea pig hearing organ. Using a pulse protocol designed to emphasize M currents with the whole-cell patch-clamp technique, voltage- and time-dependent, non-inactivating, low-threshold currents (the hallmarks of M currents) were recorded. These currents were significantly reduced by cadmium chloride. Results from RT-PCR analysis indicated that genes encoding M channel subunits KCNQ2 and KCNQ3 are expressed in the guinea pig cochlea. Our data suggest that guinea pig outer hair cells express an M-like potassium current that, following sound stimulation, may play an important role in returning the membrane potential to resting level and thus regulating outer hair cell synaptic mechanisms.
Liang
Guihua
G
Center for Hearing and Communication Research and Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
Moore
Ernest J
EJ
Ulfendahl
Mats
M
Rydqvist
Bo
B
Järlebark
Leif
L
D000818:Animals; D019256:Cadmium Chloride / Q000008:administration & dosage / Q000494:pharmacology; D017931:DNA Primers / Q000235:genetics; D006168:Guinea Pigs; D018072:Hair Cells, Auditory, Outer / Q000378:metabolism*; D007211:Indoles / Q000008:administration & dosage / Q000494:pharmacology; D051658:KCNQ2 Potassium Channel; D018408:Patch-Clamp Techniques; D026902:Potassium Channel Blockers / Q000008:administration & dosage / Q000494:pharmacology; D024642:Potassium Channels, Voltage-Gated / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D011725:Pyridines / Q000008:administration & dosage / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction
D017931:DNA Primers; D007211:Indoles; D051658:KCNQ2 Potassium Channel; D026902:Potassium Channel Blockers; D024642:Potassium Channels, Voltage-Gated; D011725:Pyridines; C061017:linopirdine; D019256:Cadmium Chloride