Korean J Otorhinolaryngol-Head Neck Surg.  2009 Aug;52(8):655-659. 10.3342/kjorl-hns.2009.52.8.655.

Isolation of Voltage Dependent Calcium Current in Chick Inner Hair Cell

• Lee SH
• Shin MC
• Ahn TH
• Kim KY
• Kim K
• Min HJ
• Park CW

• KMID: 2277079
• DOI: http://doi.org/10.3342/kjorl-hns.2009.52.8.655

Abstract

BACKGROUND AND OBJECTIVES: Voltage dependent calcium channel (VDCC) mediates calcium ion influx and controls neurotransmitter release in excitable cells. Hair cells in vertebrates cochlea are known to express L-type VDCC. The purpose of this study was to measure calcium current from hair cells to investigate basic activity and characteristics of VDCC. MATERIALS AND METHOD: We measured calcium current in hair cells of the chicken's auditory organ, the basilar papilla analogous to the mammalian cochlea, in whose L-type, dihydropyridinesensitive calcium channels predominate and in vestibular hair cells from cristae. Calcium currentthrough VDCC was isolated in voltage-clamp recording using Cesium, Tetraethylammonium, 4- aminopyridine and apamin to block the much larger potassium currents. Various concentrations of internal calcium buffer, ethylene glycol tetraacetic acid (EGTA) or 1,2-bis (o-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid (BAPTA) were used.
RESULTS
The higher the buffer concentration, the larger the current size were ; they were significantly larger in 10 mM of calcium buffer concentration (ANOVA, p< 0.05). There was no difference in calcium current between cochlear and vestibular hair cells.
CONCLUSION
We could successfully isolate stable inward calcium current from chick hair cells. This experiment can be used as a basic method to understand neurotransmission process between hair cells and afferent neurons.

Keyword

Hair cell; Calcium channel

MeSH Terms

Apamin
Calcium
Calcium Channels
Calcium Channels, L-Type
Cesium
Cochlea
Egtazic Acid
Ethylenes
Hair
Hair Cells, Vestibular
Neurons, Afferent
Neurotransmitter Agents
Organ of Corti
Potassium
Synaptic Transmission
Tetraethylammonium
Vertebrates
Apamin
Calcium
Calcium Channels
Calcium Channels, L-Type
Cesium
Egtazic Acid
Ethylenes
Neurotransmitter Agents
Potassium
Tetraethylammonium