Regulation of the CaィイD12+ィエD1 channels of rat osteoclast by the signals of bone resorption and formation

骨吸收和形成信号对大鼠破骨细胞CaiD12+D1通道的调节

基本信息

批准号：
10671361
负责人：
FUJIMOTO Yoshinori
金额：
$ 2.11万
依托单位：
Hiroshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10671361/
关键词：
osteoclast patch clamp CaィイD12+ィエD1 channel ryanodine receptor イオンチャネル

项目摘要

During bone resorption, osteoclasts are exposed to unusually high ambient CaィイD12+ィエD1. This leads to CaィイD12+ィエD1 influx and CaィイD12+ィエD1 release from intracellular CaィイD12+ィエD1 stores, which result in a sharp cytosolic CaィイD12+ィエD1 increase. Finally, the rise in cytosolic CaィイD12+ィエD1 is transduced into an inhibition of bone resorption. It has been demonstrated that a ryanodine receptor (RyR) isoform, expressed in the osteoclast plasma membrane, functions as a CaィイD12+ィエD1 channel and a CaィイD12+ィエD1 sensor. This hypothesis was suggested by the measurement of cyiosolic CaィイD12+ィエD1 concentration. However, a pathway for the CaィイD12+ィエD1 influx through the plasma membrane of osteoclast has not been identified electrophysiologically. In this study, we measured a current that can carry CaィイD12+ィエD1 in the inside-out patch clamp configuration. The current could be measured by the application of the intracellular solution containing high concentration (0.1 mM) of ruthenium red (RtR) plus 3 mM MgClィイD22ィエD2, while it was blocked by low concentration (10 μ M) of RtR. The equilibrium potential of this current was approximately +5 mV, and the conductances were 20 pS (pipette solution contained 10 mM CaClィイD22ィエD2) and 27pS (60 mM CaClィイD22ィエD2), respectively. These results are consistent with the report that RtR triggered an elevation of cytosolic CaィイD12+ィエD1 concentration only when high concentration of RtR was applied (Adebanjo OA et al. Am J Physiol 270 : F469-F475). Here, we provided evidences using an electrophysiological method that RyR expressed in the plasma membrane of osteoclasts were able to conduct CaィイD12+ィエD1 ions for the first time.

在骨吸收过程中，破骨细胞暴露于异常高的环境中 CaiD12+D1，这导致 CaiD12+D1 流入和 CaiD12+D1 从细胞内 CaiD12+D1 储存中释放，从而导致胞质 CaiD12+D1 急剧增加。胞质 CaiD12+D1 是已证明破骨细胞膜血浆中表达的兰尼碱受体 (RyR) 亚型具有 CaiD12+D1 通道和 CaiD12+D1 传感器的功能。这一假设是通过测量得出的。然而，CaiD12+D1 流入的途径是胞质 CaiD12+D1 浓度。破骨细胞的质膜尚未通过电生理学方法进行鉴定。在本研究中，我们测量了由内向外膜片钳配置中可以携带 CaD12+D1 的电流。该电流可以通过应用含有高浓度（0.1 mM）的细胞内溶液来测量。）的钌红（RtR）加3 mM浓度的MgCl2D2，而被低浓度（10 μM）的RtR阻断的平衡电位。该电流约为+5 mV，电导分别为20 pS（移液器溶液含有10 mM CaClD22D2）和27 pS（60 mM CaClD22D2）。这些结果与RtR触发胞质CaD12+D1浓度升高的报告一致。仅当应用高浓度的 RtR 时（Adebanjo OA 等人 Am J Physiol 270：F469-F475）在此，我们使用电生理学方法首次提供了破骨细胞质膜中表达的RyR能够传导Ca2+D1离子的证据。