Contractile properties of single skinned fibres from the extraocular muscles, the levator and superior rectus, of the rabbit.

Contractile properties of single skinned fibres from the extraocular muscles, the levator and superior rectus, of the rabbit.
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兔子眼外肌、提肌和上直肌的单皮纤维的收缩特性。

DOI:
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发表时间:
1994
期刊:
Journal of Physiology
影响因子:
--
通讯作者:
D. Williams
D. Williams
中科院分区:
--
文献类型:
--
作者:
G. Lynch;B. Frueh;D. Williams

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1.从家兔身上切下上级直肌和上睑提肌(提肌)(两种眼外肌),并在-20 ℃下储存在甘油基溶液中,以制备单根带皮纤维。2.测定了单个眼外肌纤维的Ca(2+)和Sr(2+)激活的等长收缩特性。根据纤维的生理特性,将其分成离散的组或纤维类型。发现上级直肌和提肌均由与其他哺乳动物肌肉的快肌和慢肌纤维(包括I型、IIA型和IIB型纤维)具有相似收缩特性的纤维组成。3.除了眼外肌中存在正常的经典纤维类型外,还存在大量来自两种肌肉的纤维,这些纤维在单个收缩单位内表现出混合的快缩和慢缩收缩特性。在所取样的纤维中,混合纤维包括提肌中的第二大群体(7/19,37%)和上级直肌中的最大纤维群体(11/31,35.5%)。这些结果与文献中的组织化学和免疫组织化学报告一致,文献中的组织化学和免疫组织化学报告表明沿着眼外肌纤维长度存在快肌球蛋白和慢肌球蛋白。4.与其他哺乳动物肢体肌纤维相比,眼外肌纤维表现出较低的绝对最大力。然而,当校正纤维横截面积时,最大张力发展在哺乳动物肢体肌纤维的正常范围内,除了一组(IIA型)快缩纤维表现出显著较低的最大张力。5.大部分具有复合快速和缓慢收缩特征的纤维的存在突出了这些肌肉的功能和形态复杂性。据推测,这些混合纤维的功能意义可能是提供或增强眼睛和眼睑的细微、精确运动的分辨率。
1. The superior rectus and levator palpebrae superioris (levator), two of the extraocular muscles, were dissected from the rabbit and stored in a glycerol‐based solution at ‐20 degrees C in order to prepare single, skinned fibres. 2. The Ca(2+)‐ and Sr(2+)‐activated isometric contractile properties were determined for individual extraocular muscle fibres. Fibres were separated into discrete groups or fibre types on the basis of their physiological characteristics. The superior rectus and levator muscles were both found to consist of fibres which exhibited similar contractile characteristics to fast‐ and slow‐twitch fibres from other mammalian muscle, including type I, type IIA and type IIB fibres. 3. As well as the existence of the normal, classical fibre types in extraocular muscle there were also a large number of fibres from both muscles which exhibited mixed fast‐ and slow‐twitch contractile characteristics within the single contracting unit. Of the fibres sampled, the mixed fibres comprised the second largest population (7/19, 37%) in the levator and the largest fibre population in the superior rectus (11/31, 35.5%). These results are consistent with histochemical and immunohistochemical reports in the literature which suggest the co‐existence of fast and slow myosin along the length of the extraocular muscle fibres. 4. Extraocular muscle fibres exhibited lower absolute maximum forces compared with other mammalian limb muscle fibres. However, when corrected for fibre cross‐sectional area, the maximum tension development was within the normal range for mammalian limb muscle fibres, except for one group (type IIA) of fast‐twitch fibres which exhibited significantly lower maximal tension. 5. The existence of a large proportion of fibres with composite fast‐ and slow‐twitch characteristics highlights the functional and morphological complexity of these muscles. It is postulated that the functional significance of these mixed fibres may be to provide or enhance the resolution for subtle, precise movements of the eye and eyelid.
DOI: 10.1113/jphysiol.1988.sp017036
发表时间: 1988
期刊: The Journal of physiology
影响因子: --
作者:
Metzger,JM;Moss,RL
通讯作者: Moss,RL
成年兔比目鱼肌单纤维的缩短速度与肌球蛋白重链组成相关。
DOI: --
发表时间: 1985
期刊: The Journal of biological chemistry
影响因子: --
作者:
Reiser,PJ;Moss,RL;Giulian,GG;Greaser,ML
通讯作者: Greaser,ML
发育中比目鱼肌单纤维中肌球蛋白转变的功能意义。
DOI: 10.1152/ajpcell.1988.254.5.c605
发表时间: 1988
期刊: The American journal of physiology
影响因子: --
作者:
Reiser,PJ;Kasper,CE;Greaser,ML;Moss,RL
通讯作者: Moss,RL