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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Ca ~（2+）D12+ Ca ~（2+）D1。这导致细胞内Ca ~（2+）D_12 + Ca ~（2+）D_1内流和Ca ~（2+）D_12 + Ca ~（2+）D_1从细胞内Ca ~（2+）D_12 + Ca ~（2+）D_1库中释放，这导致细胞溶质Ca ~（2+）D_12 + Ca ~（2+）D_1急剧增加。最后，细胞溶质Ca ~（2+）D_12 + Ca ~（2+）D_1的升高被转化为骨吸收的抑制。已经证明，在破骨细胞质膜中表达的Ryanodine受体（RyR）同种型作为Ca ~（2+）D12+ Ca ~（2+）D1通道和Ca ~（2+）D12+ Ca ~（2+）D1传感器起作用。通过测量环胞质Ca ~（2+）D_12 + Ca ~（2+）D_1的浓度证实了这一假设。然而，钙通道D12+钙通道D1通过破骨细胞的质膜流入的途径尚未确定电生理。在这项研究中，我们测量了一个电流，可以携带钙通道D12+钙通道D1的内面向外膜片钳配置。用高浓度（0.1mM）钌红（RtR）+3mM MgCl-[2，3-D_2，3-D_2]的胞内溶液可测得该电流，而低浓度（10 μ M）RtR可阻断该电流。该电流的平衡电位约为+5 mV，电导分别为20 pS（移液器溶液含有10 mM CaCl水溶液D22）和27 pS（60 mM CaCl水溶液D22）。这些结果与仅当应用高浓度的RtR时RtR触发细胞溶质Ca ~（2+）D12+ Ca ~（2+）D1浓度升高的报道一致（Adebanjo OA等，Am J Physiol 270：F469-F475）。在此，我们首次用电生理学方法证明了破骨细胞质膜上表达的RyR能够传导Ca ~（2+）D_12 + Ca ~（2+）D_1离子。