Osmotic compression of single cardiac myocytes eliminates the reduction in Ca2+ sensitivity of tension at short sarcomere length.
Osmotic compression of single cardiac myocytes eliminates the reduction in Ca2+ sensitivity of tension at short sarcomere length.
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单心肌细胞的渗透压缩消除了短肌节长度下 Ca2+ 张力敏感性的降低。
DOI：
10.1161/01.res.77.1.199
复制
发表时间：
1995
影响因子：
20.1
通讯作者：
Moss,RL
中科院分区：
文献类型：
--
作者：
McDonald,KS;Moss,RL
根据Frank-Starling关系，心输出量作为心室舒张末期容积的函数而变化。该关系的细胞基础被认为涉及张力的Ca 2+敏感性的长度依赖性变化;即，随着心肌中肌节长度的增加，张力的Ca 2+敏感性也增加。这种效应的一个可能的解释是，随着肌肉长度的增加，肌细胞直径的减小减少了粗丝和细丝之间的横向间距，从而增加了与肌动蛋白交叉桥相互作用的可能性。为了验证这一观点，我们测量了单层皮肤心肌细胞的渗透压对张力的Ca 2+敏感性的影响。从大鼠酶消化心室的单个肌细胞连接到一个力传感器和压电翻译器，和张力-pCa的关系，随后在短肌节长度（SL），在相同的短SL的存在下，2.5%的葡聚糖，并在长SL的特点。当SL从1.85 μm增加到1.25 μm时，半最大张力（即pCa 50）的pCa（−log[Ca 2 +]）从5.54±0.09增加到5.65±0.10（n=7，平均值±SD，P<0.001）。短肌细胞的渗透压也增加了张力的Ca ~（2+）敏感性，使张力-pCa关系与[Ca ~（2+）]水平的变化类似于长肌细胞的变化（pCa ~（50），5.68±0.11）。这些结果支持的想法，在心肌中的张力的Ca 2+的敏感性的长度依赖性产生在很大程度上从伴随SL的变化的丝间晶格间距的变化。
According to the Frank-Starling relation, cardiac output varies as a function of end-diastolic volume of the ventricle. The cellular basis of the relation is thought to involve length-dependent variations in Ca2+sensitivity of tension; ie, as sarcomere length is increased in cardiac muscle, Ca2+sensitivity of tension also increases. One possible explanation for this effect is that the decrease in myocyte diameter as muscle length is increased reduces the lateral spacing between thick and thin filaments, thereby increasing the likelihood of cross-bridge interaction with actin. To examine this idea, we measured the effects of osmotic compression of single skinned cardiac myocytes on Ca2+sensitivity of tension. Single myocytes from rat enzymatically digested ventricles were attached to a force transducer and piezoelectric translator, and tension-pCa relations were subsequently characterized at short sarcomere length (SL), at the same short SL in the presence of 2.5% dextran, and at long SL. The pCa (−log[Ca2+]) for half-maximal tension (ie, pCa50) increased from 5.54±0.09 to 5.65±0.10 (n=7, mean±SD,P<.001) as SL was increased from ≈1.85 to ≈2.25 μm. Osmotic compression of myocytes at short length also increased Ca2+sensitivity of tension, shifting tension-pCa relations to [Ca2+] levels similar to those observed at long length (pCa50, 5.68±0.11). These results support the idea that the length dependence of Ca2+sensitivity of tension in cardiac muscle arises in large part from the changes in interfilament lattice spacing that accompany changes in SL.
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DOI：
10.1016/s0021-9258(17)43827-0
发表时间：
1983-12
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Z. Grabarek;J. Grabarek;Paul C. LeavisS;J. Gergely
通讯作者：
Z. Grabarek;J. Grabarek;Paul C. LeavisS;J. Gergely
强结合肌球蛋白类似物对带皮骨骼肌纤维钙敏感机械特性的影响。
DOI：
--
发表时间：
1992
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Swartz,DR;Moss,RL
通讯作者：
Moss,RL
DOI：
10.1152/ajpcell.1987.253.1.c90
发表时间：
1987-07
期刊：
The American journal of physiology
影响因子：
--
作者：
P. Hofmann;F. Fuchs
通讯作者：
P. Hofmann;F. Fuchs
带皮心肌细胞的收缩激活对肌节长度的依赖性
影响因子：
64.8
作者：
A. Fabiato;F. Fabiato
通讯作者：
F. Fabiato
带皮心肌束中的结合钙和力量发展：肌节长度的影响。
影响因子：
5
作者：
Hofmann,PA;Fuchs,F
通讯作者：
Fuchs,F