权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Study in calcium in muscle by intracellular organelles

通过细胞内细胞器研究肌肉中的钙

基本信息

批准号：
09044243
负责人：
TSUTSUI Izuo
金额：
$ 2.69万
依托单位：
Okazaki National Research Institutes
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

项目摘要

We have investigated the role of the intracelluar organelles to the function of the muscle contractility and the relaxation mechanism. At least there are many organelles which control the contraction and relaxation in muscle cell such as sarcoplasmic reticulum (SR), transvers tubular structure (T system), Ca pump, Na/Ca exchange mechanism, Ca channel, ryanodine receptor, DHP receptor and so on. To testify the role of such organe lles, we focused on the animals lucking these organelles. The typical example is the marine plankton Doliolum, which lucking the T system and SR together, shows the essential necessity of extracellular Ca for its contraction and the Ca get in the muscle through voltage gated Ca channel is extruded only by the Na/Ca exchange mechanism not by Ca pumpinging system, suggesting that the SR is not essential for muscle contraction and cytoplasmic Ca sequestering. On the other hard, by frequent stimulation Doliolum stop its movement for a while, indicating once the cytoplasmic Ca exceeded thecertain level it took a long time to extrude and lower intacellular Ca. Thus SR could play a role of continuous lowering the cytop)lasmic Ca level and fine tuning of the intracellular Ca level, ON the other hand the animal with 'T and SR organelles the activity of Na/Ca exchange for lowering intracellular Ca level is limited, strongly suggesting the transition of Ca control mechanism by developing the T' and SR organelles.

我们研究了细胞内细胞器在肌肉收缩功能和舒张机制中的作用。至少有许多细胞器控制着肌肉细胞的收缩和舒张，如肌浆网（SR）、横管结构（T系统）、钙泵、Na/Ca交换机制、钙通道、兰尼碱受体、DHP受体等，为了证实这些细胞器的作用，我们着重研究了缺乏这些细胞器的动物。典型的例子是海洋浮游生物Doliphantae，它同时具有T系统和SR系统，表明细胞外Ca对它的收缩是必不可少的，通过电压门控Ca通道进入肌肉的Ca仅通过Na/Ca交换机制排出，而不是通过Ca泵系统排出，表明SR不是肌肉收缩和细胞质Ca螯合所必需的。另一方面，在频繁刺激的情况下，Doliphin的运动会暂时停止，表明细胞内Ca一旦超过一定水平，细胞内Ca的排出和降低需要较长的时间。因此，SR可以起到持续降低细胞内Ca水平和微调细胞内Ca水平的作用。另一方面，具有“T”和SR细胞器的动物，降低细胞内Ca水平的Na/Ca交换活性有限，这强烈地暗示了通过发育“T”和SR细胞器实现的Ca控制机制的转变。