期刊
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES
卷 288, 期 1950, 页码 -出版社
ROYAL SOC
DOI: 10.1098/rspb.2020.2895
关键词
myosin cross-bridges intact muscle
资金
- National Science Foundation [1656450]
- American Heart Association [19TPA34860008]
- National Institutes of Health [R01 HL149164]
- Army Research Office [ARO 66554-EG]
- Division Of Integrative Organismal Systems
- Direct For Biological Sciences [1656450] Funding Source: National Science Foundation
Muscle contraction results from force-generating interactions between myosin and actin, with factors influencing cross-bridge kinetics at the molecular level propagating through tissues to modulate whole-muscle function. Researchers found that cross-bridge kinetics vary with whole-muscle length during intact, isometric contraction, suggesting a feedback pathway between muscle function and cross-bridge activity. The study highlights the complexity of muscle contraction and the potential impact of length-dependent cross-bridge kinetics on force generation and energetics.
Muscle contraction results from force-generating cross-bridge interactions between myosin and actin. Cross-bridge cycling kinetics underlie fundamental contractile properties, such as active force production and energy utilization. Factors that influence cross-bridge kinetics at the molecular level propagate through the sarcomeres, cells and tissue to modulate whole-muscle function. Conversely, movement and changes in the muscle length can influence cross-bridge kinetics on the molecular level. Reduced, single-molecule and single-fibre experiments have shown that increasing the strain on cross-bridges may slow their cycling rate and prolong their attachment duration. However, whether these strain-dependent cycling mechanisms persist in the intact muscle tissue, which encompasses more complex organization and passive elements, remains unclear. To investigate this multi-scale relationship, we adapted traditional step-stretch protocols for use with mouse soleus muscle during isometric tetanic contractions, enabling novel estimates of length-dependent cross-bridge kinetics in the intact skeletal muscle. Compared to rates at the optimal muscle length (L-o), we found that cross-bridge detachment rates increased by approximately 20% at 90% of L-o (shorter) and decreased by approximately 20% at 110% of L-o (longer). These data indicate that cross-bridge kinetics vary with whole-muscle length during intact, isometric contraction, which could intrinsically modulate force generation and energetics, and suggests a multi-scale feedback pathway between whole-muscle function and cross-bridge activity.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据