Maximum shortening velocity and myosin heavy-chain isoform expression in human masseter muscle fibers.
Maximum shortening velocity and myosin heavy-chain isoform expression in human masseter muscle fibers.
复制标题
人咬肌纤维中的最大缩短速度和肌球蛋白重链亚型表达。
DOI：
10.1177/00220345010800091401
复制
发表时间：
2001
影响因子：
7.6
通讯作者：
Sciote,JJ
中科院分区：
文献类型：
--
作者：
Morris,TJ;Brandon,CA;Horton,MJ;Carlson,DS;Sciote,JJ
虽然众所周知，人类咬肌有不寻常的肌球蛋白重链蛋白的共同表达，但单个纤维的细胞动力学尚未得到测试。在这里，我们检查肌球蛋白重链蛋白的含量是否与纤维缩短速度密切相关，就像之前在其他人类肌肉中所报道的那样，或者是否这些蛋白质与纤维缩短速度没有很好的相关性，就像之前在大鼠肌肉中所证明的那样。在15°C下对单个皮肤的人咬肌纤维进行松弛测试记录，发现最大缩短速度通常比在人类四肢肌肉中记录的速度慢得多，变化也更大。记录中最慢的纤维的最大缩短速度(V0)值为0.027肌长·S-1，比之前在人类中测量的最慢的I型纤维慢几倍。相比之下，人类四肢肌肉控制组产生的V0测量结果与之前发表的结果相当。凝胶电泳法分析发现，63%的咬肌纤维含有纯的I型MyHC，其余的以IIA和IIX亚型的不同组合方式主要共表达I型。咬肌纤维中的VO形成一个连续体，在这个连续体中与MyHC亚型含量没有明显的关系。
While human masseter muscle is known to have unusual co-expression of myosin heavy-chain proteins, cellular kinetics of individual fibers has not yet been tested. Here we examine if myosin heavy-chain protein content is closely correlated to fiber-shortening speed, as previously reported in other human muscles, or if these proteins do not correlate well to shortening speeds, as has been demonstrated previously in rat muscle. Slack-test recordings of single, skinned human masseter fibers at 15°C revealed maximum shortening velocities generally slower and much more variable than those recorded in human limb muscle. The slowest fiber recorded had a maximum shortening velocity (V0) value of 0.027 muscle lengths ·s-1, several times slower than the slowest type I fibers previously measured in humans. By contrast, human limb muscle controls produced V0measurements comparable with previously published results. Analysis by gel electrophoresis found 63% of masseter fibers to contain pure type I MyHC and the remainder to co-express mostly type I in various combinations with IIA and IIX isoforms. Vo in masseter fibers forms a continuum in which no clear relationship to MyHC isoform content is apparent.