ARCHITECTURAL, HISTOCHEMICAL, AND CONTRACTILE CHARACTERISTICS OF A UNIQUE BIARTICULAR MUSCLE - THE CAT SEMI-TENDINOSUS
ARCHITECTURAL, HISTOCHEMICAL, AND CONTRACTILE CHARACTERISTICS OF A UNIQUE BIARTICULAR MUSCLE - THE CAT SEMI-TENDINOSUS
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DOI：
10.1152/jn.1982.48.1.192
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发表时间：
1982-01-01
影响因子：
2.5
通讯作者：
EDGERTON, VR
中科院分区：
文献类型：
--
作者：
BODINE, SC;ROY, RR;EDGERTON, VR
猫的半腱肌（ST）由2组解剖学上不同的纤维组成，这些纤维通过致密的结缔组织带串联连接，该结缔组织带将肌肉分成近端和远端隔室，每个隔室具有单独的神经支配。在近端激活（STp）、远端激活（STd）和全肌激活（ST）3种刺激条件下，研究了ST的等长和等张收缩特性。确定了每个隔室的结构和组织化学特征。STp和STd的纤维类型组成相似，大多数纤维对碱性肌原纤维ATP酶染色较深。STd的肌纤维长度是STp的两倍。2个隔室的横截面积相似。所有3种刺激条件的原位最大等长张力（Po）相同。最大抽搐张力（Pt）最大时ST被激活，最小时，只有STp被激活。对于所有3种条件，达到峰值张力的时间（TPT）和半松弛时间（1/2 RT）相同。绝对最大缩短速度（Vmax）显示了一个有序的进展速度与纤维长度。当STd（424 . 26 mm/s）和STp（224 . 23 mm/s），总和与ST获得的Vmax大致相同（624 . ±-. 30 mm/s）。在所有3种条件下，在附着肌腱处记录的缩短的固有速度（mm/s/1000个肌节）相同。Po值的相同性质证明了结构设计的重要性，特别是生理横截面积，在确定肌肉的潜在力产生。对于每种刺激条件，Pt值显著不同。这些差异可能部分受到肌肉结缔组织单位的刚度-顺应性特性的影响，该特性随ST肌的不同激活状态而变化。所有3种条件下TPT和1/2 RT值的相似性说明了等长速度相关参数与肌肉结构的独立性。然而，在绝对Vmax数据的差异，揭示了缩短的最大速度和纤维长度之间的正相关关系。这些数据证明了神经运动命令与每个肌节的结构以及生化特性相匹配的必要性（例如，肌球蛋白ATP酶和肌浆网）在体内控制力和速度。
The semitendinosus (ST) muscle of the cat consists of 2 anatomically distinct sets of fibers connected in series by a dense connective tissue band that divides the muscle into a proximal and distal compartment, each having separate innervation. Isometric and isotonic contractile properties of the ST were studied for 3 stimulation conditions: proximal activated (STp), distal-activated (STd), whole muscle activated (ST). The architectural and histochemical profiles of each compartment were determined. The fiber type composition was similar in the STp and STd, with the majority of the fibers staining darkly for alkaline myofibrillar ATPase. The muscle fibers of the STd were twice as long as the fibers of the STp. The cross-sectional areas of the 2 compartments were similar. The in situ maximum isometric tension (Po) was identical for all 3 stimulation conditions. The maximum twitch tension (Pt) was greatest when ST was activated and least when only the STp was activated. The time to peak tension (TPT) and half relaxation times (1/2 RT) were the same for all 3 conditions. The absolute maximal shortening velocity (Vmax) revealed an orderly progression of speeds in relation to the fiber length. When the Vmax of the STd (424 .+-. 26 mm/s) and STp (224 .+-. 23 mm/s) were added, the sum was approximately the same as the Vmax obtained for the ST (624 .+-. 30 mm/s). The intrinsic speed of shortening (mm/s per 1000 sarcomeres) recorded at the common tendon of insertion was the same for all 3 conditions. The identical nature of the Po values demonstrated the significance of the architectural design, specifically the physiological cross-sectional area, in determining the potential force production of a muscle. The Pt values were significantly different for each stimulation condition. These differences were probably influenced in part by the stiffness-compliance properties of the muscle-connective tissue unit, which varied with different activation states of the ST muscle. The similarity in TPT and 1/2 RT values for all 3 conditions illustrated the independence of the isometric speed-related parameters from the architecture of the muscle. The differences in the absolute Vmax data, however, revealed a positive relationship between the maximum speed of shortening and the fiber length. These data demonstrate the necessity of the neuromotor command being matched with the architectural as well as the biochemical properties of each sarcomere (e.g., myosin ATPase and sarcoplasmic reticulum) of the muscles in the control of forces and velocities in vivo.