병아리 내이 유모세포에서 전압의존성 칼슘전류의 분리 측정
Isolation of Voltage Dependent Calcium Current in Chick Inner Hair Cell
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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 current through 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.
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 current through 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.
참고문헌 (19)
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