Yamashita T, Amano H, Harada N, Su Z L, Kumazawa T, Tsunoda Y, Tashiro Y
Department of Otolaryngology, Kansai Medical University, Osaka, Japan.
Acta Otolaryngol. 1990 Mar-Apr;109(3-4):256-62. doi: 10.3109/00016489009107441.
Intracellular distribution of cytoplasm-free Ca2+ concentrations ((Ca2+)i) and dynamic changes during stimulation of viable hair cells were studied using digital imaging microscopy and the Ca2(+)-sensitive dye fura-2. (Ca2+)i was visualized on pseudo-colour images and three-dimensional computer graphics. In the resting state, the intra-cellular distribution of (Ca2+)i in both the outer and inner hair cells was heterogeneous, and the amount of (Ca2+)i in most of the peripheral cytoplasm just beneath the plasma membrane was greater than that throughout the entire cytoplasm. Cell depolarization, induced by elevated K+, led to an increase in (Ca2+)i in the outer hair cells. The increase in (Ca2+)i was not observed under conditions of depolarization in Ca2(+)-free medium. These observations are interpreted to mean that the increase in (Ca2+)i is induced by depolarization with the result that there is an influx of extracellular Ca2+ into the cytoplasm. When Mn2+ was applied during depolarization, a fluorescence quenching occurred. By such means the site of Ca2+ channels was elucidated.
利用数字成像显微镜和钙离子敏感染料fura-2，研究了活毛细胞在刺激过程中无细胞质钙离子浓度（(Ca2+)i）的细胞内分布及动态变化。(Ca2+)i在伪彩色图像和三维计算机图形上可视化。在静息状态下，外毛细胞和内毛细胞中(Ca2+)i的细胞内分布是不均匀的，质膜下方大部分周边细胞质中的(Ca2+)i量大于整个细胞质中的量。由高钾诱导的细胞去极化导致外毛细胞中(Ca2+)i增加。在无钙培养基中去极化条件下未观察到(Ca2+)i增加。这些观察结果被解释为意味着(Ca2+)i增加是由去极化诱导的，结果是细胞外Ca2+流入细胞质。当在去极化过程中应用Mn2+时，发生荧光猝灭。通过这种方式阐明了钙离子通道的位置。
