Changes in rabbit jaw-muscle activity parameters in response to reduced masticatory load
Changes in rabbit jaw-muscle activity parameters in response to reduced masticatory load
复制标题
DOI：
10.1242/jeb.037762
复制
发表时间：
2010-03-01
影响因子：
2.8
通讯作者：
Langenbach, G. E. J.
中科院分区：
文献类型：
--
作者：
Gruenheid, T.;Brugman, P.;Langenbach, G. E. J.
食物的机械特性影响咀嚼过程中颌部闭合肌肉的神经肌肉活动。然而，尚不清楚咀嚼负荷的长期变化如何影响颌部肌肉的活动状况。为了阐明减少咀嚼负荷对三种功能不同的下颌肌肉日常习惯性活动的影响，我们对 16 只 7 至 20 周龄的雄性兔子的咬肌、颞肌和二腹肌的肌电图进行了遥测记录。从八周龄开始，实验动物喂食的颗粒明显比对照动物软。每日肌肉活动通过肌肉使用的相对持续时间（工作时间）、与多个活动水平相关的爆发次数和爆发长度来量化。在食物硬度变化后的两周内，在最大活动的5%和10%时，实验组的每日工作时间和咬肌爆发次数显着低于对照组。相比之下，食物硬度的改变并没有显着影响颞肌和二腹肌的活动特征。研究结果表明，咀嚼负荷的减少会降低闭合颌肌肉的神经肌肉活动，而闭合颌肌肉主要负责咀嚼过程中产生力。这种下降在食物硬度变化后的几周内最为明显，并且仅限于反映咀嚼过程中肌肉收缩的活动水平。这些发现支持这样的结论：咀嚼系统在下颌肌肉的活动概况中几乎没有表现出饮食特异性的长期变化。
Mechanical food properties influence the neuromuscular activity of jaw-closing muscles during mastication. It is, however, unknown how the activity profiles of the jaw muscles are influenced by long-term alterations in masticatory load. In order to elucidate the effect of reduced masticatory load on the daily habitual activity profiles of three functionally different jaw muscles, the electromyograms of the masseter, temporalis and digastric muscles were recorded telemetrically in 16 male rabbits between seven and 20 weeks of age. Starting at eight weeks of age the experimental animals were fed significantly softer pellets than the control animals. Daily muscle activity was quantified by the relative duration of muscle use (duty time), burst number and burst length in relation to multiple activity levels. The daily duty time and burst number of the masseter muscle were significantly lower in the experimental group than in the control group at 5% and 10% of the maximum activity during the two weeks following the change in food hardness. By contrast, altered food hardness did not significantly influence the activity characteristics of the temporalis and digastric muscles. The findings suggest that a reduction in masticatory load decreases the neuromuscular activity of the jaw-closing muscles that are primarily responsible for force generation during mastication. This decrease is most pronounced in the weeks immediately following the change in food hardness and is limited to the activity levels that reflect muscle contractions during chewing. These findings support the conclusion that the masticatory system manifests few diet-specific long-term changes in the activity profiles of jaw muscles.