Potassium currents induced by hydrostatic pressure modulate membrane potential and transmitter release in vestibular type II hair cells

被引:0
作者
Thien An Duong Dinh
Thorsten Haasler
Georg Homann
Eberhard Jüngling
Martin Westhofen
Andreas Lückhoff
机构
[1] RWTH Aachen,Institute of Physiology, Medical Faculty
[2] RWTH University Aachen,Department of Oto
来源
Pflügers Archiv - European Journal of Physiology | 2009年 / 458卷
关键词
Capacitance; Meniere’s disease; Endolymphatic hydrops; Ca; currents; Patch clamp; Current clamp;
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摘要
Vestibular type II hair cells respond to increases in the hydrostatic pressure with pressure-dependent K+ currents. We examined whether such currents may modulate transmitter release (assessed as membrane capacitance increments) by altering membrane potentials and voltage-gated Ca2+ currents. Capacitance increments were dependent on voltage-gated Ca2+ influx. Stimulating currents (0.7 nA) in current clamp induced depolarisations that were more negative by 8.7 ± 2.1 mV when the bath height was elevated from 0.2 to 0.5 cm. In voltage clamp, protocols were used that simulated the time course of the membrane potential in current clamp at either low (control) or high hydrostatic pressure (high bath). The low bath protocol induced significantly larger Ca2+ currents and increases in capacitance than the high bath protocol. We conclude that pressure-dependent K+ currents may alter the voltage response of vestibular hair cells to an extent critical for Ca2+ currents and transmitter release. This mechanism may contribute to vestibular dysfunction in Meniere’s disease.
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