权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Dynamic mechanical-properties in skinned masticatory muscles

带皮咀嚼肌的动态机械特性

基本信息

批准号：
02670843
负责人：
SAEKI Yasutake
金额：
$ 1.02万
依托单位：
Tsurumi University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

项目摘要

To mtudy the mechanical and metabolic properties of jaw muscles, we analyzed the Ca^<2+> sensitivity of isometric tension development, the ATPase activity, the maximum shortening velocity, and the tension transients in response to small(1 % of muscle length)step length perturbations in glycerinated masticatory muscles (1) of monkey whose mandibular movement seems to be quite similar to that of human and (2) of bite-opened guinea pig whose mandibular movement was focibly limited. In monkey preparations (reasseter, temporalis, superior and inferior lateral pterygoid), the isometric tension increased in sigmoid fashion with an increase in Ca^<2+> concentration. The pea for half maximum tension was 5.88 in masseter, 5.84 in tempolaris, 5.6 in superior lateral pterygoid and 5.90 in inferior lateral pterygoid. The maximum tension was highest in masseter (about 15 g/mm^2) and lowest in superior lateral pterygoid (about 9 g/mm^2). The time constant of the tension transient, which reflects the rate of cross-bridge cycling, was in the-order of masseter<tempolaris = superior lateral pterygoid<inferior lateral pterygoid., In bite-opened guinea pig preparations (masseter and digastric muscles), the Ca^<2+> sensitivity for tension development was decreased with bite-opening. The maximum tension increased significantly only in the masseter of 1-week-bite-opened guinea'pig, and the maximum shortening velocity was increased only in the 1-week-bite-opened digastric muscle. ATPase activity was always increased with an increase in tension development. However, the tension cost (ATPase activity/tension) was decreased only in the masseter of 1-week- bite-opened guinea pig. These results suggest that after 1-week-biteopening, the masseter produces greater tehsion by consuming ATP more economically, while the digastric decreases Ca^<2+> sensitivity and increases the maximum shortening velocity without changing the tension cost.

为了研究颌骨肌肉的力学和代谢特性，我们分析了等长拉伸发展的Ca^<2+>敏感性、ATP酶活性、最大缩短速度、和张力瞬态响应小（肌肉长度的1%）甘油化咀嚼肌的步长扰动（1）猴的下颌运动似乎与人的下颌运动非常相似，（2）咬-开放的豚鼠，其下颌运动被局限性地限制。在猴标本（再定肌、颞肌、上级和下翼外肌）中，随着Ca^<2+>浓度的增加，等长张力以S形方式增加。咬肌、颞肌、上级翼外肌和翼下外肌的半最大张力峰值分别为5.88、5.84、5.6和5.90。最大张力在咬肌最高（约15 g/mm ^2），在上级翼外肌最低（约9 g/mm ^2）。反映跨桥运动速度的张力瞬变时间常数为咬肌<颞肌=上级翼外肌<翼下外肌。在咬开的豚鼠标本（咬肌和二腹肌）中，随着咬开，Ca^2+对张力发展的敏感性降低。咬肌最大张力仅在咬开1周后显著增加，二腹肌最大缩短速度仅在咬开1周后显著增加。ATP酶活性总是随着张力的增加而增加。然而，张力成本（ATP酶活性/张力）仅在咬开1周的豚鼠咬肌中降低。结果表明，咬开1周后，咬肌通过消耗ATP而产生更大的张力，而二腹肌降低了Ca^2+敏感性，并增加了最大缩短速度，但张力成本不变。