INTRACELLULAR CALCIUM VARIATIONS EVOKED BY MECHANICAL STIMULATION OF MAMMALIAN ISOLATED VESTIBULAR TYPE-I HAIR-CELLS

被引:13
作者
CHABBERT, C
GELEOC, G
LEHOUELLEUR, J
SANS, A
机构
[1] Laboratoire de Neurophysiologie sensorielle et cellulaire, Université de Montpellier II U254 INSERM, Montpellier Cedex 05, F-34095, place E. Bataillon
来源
PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY | 1994年 / 427卷 / 1-2期
关键词
FURA-2; GUINEA-PIG; TYPE I VESTIBULAR HAIR CELLS; CALCIUM VARIATIONS; MECHANOTRANSDUCTION;
D O I
10.1007/BF00585956
中图分类号
Q4 [生理学];
学科分类号
071003 ;
摘要
The variations of intracellular free calcium concentration ([Ca2+](i)) were recorded on-line from guinea-pig isolated vestibular sensory cells using a fura-2 fast fluorescent photometry system, during mechanical displacements of the hair bundle. Repetitive displacements of the hair bundle towards the kinocilium (posi tive stimulation 7 degrees, 300ms, 2Hz for 10 s), revealed [Ca2+](i) variations detectable only in the cuticular plate. [Ca2+](i) increased from 105 to 145 nM. Single mechanical displacements of the hair bundle (7 degrees, 200 ms, 0.5Hz) evoked increases of [Ca2+](i) from 50 +/- 23 nM to 139 +/- 79 (n = 12). In the opposite direction, the mechanical stimulations (8 degrees, 400 ms, 0.5Hz) evoked a decrease of [Ca2+](i) from 68 +/- 17 nM to 37 +/- 12 nM (n = 8). The variations of [Ca2+](i) detected in the cuticular plate during positive displacements of the hair bundle were reversibly abolished in the presence of 100 mu M gentamicin and they could not be evoked in 0.1 mM calcium in the external medium. From these experiments, it has been concluded that the [Ca2+](i) variations recorded in the cuticular plate were due to a limited entry of calcium ions through transduction channels localized in the hair bundle. The typical kinetics of variations of [Ca2+](i) evoked during positive displacements of the hair bundle should account for the presence of strong calcium regulation systems in the hair bundle and cuticular plate.
引用
收藏
页码:162 / 168
页数:7
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