【摘要】 目的　研究不同生长发育期大鼠口腔运动肌肉的收缩特性 ,以期对口腔功能改变对肌肉收缩特性的影响进行评价。方法　对 4、6、8周龄 Wistar雄性大鼠各 15只深度麻醉后 ,在自制的电刺激 -力测试装置上测试并记录了大鼠单侧嚼肌 (MM)、二腹肌前腹 (DM)、翼外肌 (L PM)在电刺激下的时间 -收缩力关系曲线 ,得出了它们在电刺激下主动收缩的收缩速度、完全松弛时间、最大收缩力。并分析了这些数据之间的关系。结果　在单一刺激下 ,4、6、8周龄大鼠 MM的收缩时间分别为 0 .18± 0 .0 1s,0 .16± 0 .0 1s,0 .16± 0 .0 2 s,收缩力分别为 4 .83± 0 .4 8g、5 .96± 1.2 1g、9.85± 1.93g;DM的收缩时间为 0 .34± 0 .0 3s、0 .36± 0 .0 4 s、0 .17± 0 .0 1s,收缩力分别为 :3.80±0 .4 0 g、4 .71± 0 .73g、8.5 9± 1.4 8g,L PM的收缩时间为 0 .37± 0 .0 4 s、0 .2 4± 0 .0 3s、0 .2 4± 0 .0 2 s,收缩力分别为 5 .38± 1.0 5 g、10 .70± 2 .76 g、34.95± 12 .2 g;各肌群收缩力随刺激频率增加明显加大 ,挛缩时达到最大值。结论　在单一刺激下三种肌群的收缩速度在快速生长期都在加快 ,MM、L PM显著加快期为 4到 6周 ,DM则为 6到8周。所有肌群收缩力快速增长期为 6到 8周更多还原

【Abstract】 Objective This study was aimed to evaluate the effect of functional change in oral cavity on the contraction peculiarity of the muscles that control the moving of the jaw in different time of growth. Methods Fifteen male Wistar rats 4, 6 and 8 weeks old were used in this experiment. After deep anesthesia, the masseter muscles(MM), digastric muscles(DM) and lateral pterygoid muscles(LPM) were stimulated in the apartment made by the present authors. The curves that express the relations of force with electric stimulation were recorded, and the relationships between the speed and force of twitch were analyzed. Results The maximal forces of twitch of the 8 week old rats’ MM, DM, LPM were 61.7±14.4 g, 86.4±25.1 g and 175.3±39.4 g respectively. When a single electric stimulus stimulated the muscles, the speed of twitch increased with the growth of the rats. As for MM and LPM, the speed markedly increased with the growing of rats from 4 weeks old to 6 weeks old; as for DM, it increased in rats growing from 6 weeks old to 8 weeks old. Conclusion The quickest time of growth of the muscles that control the moving of the jaw of rat is a period from 6 weeks to 8 weeks old and the forces of contraction and twitch increase markedly.更多还原