不同乳酸浓度对骨骼肌变力状态的影响

观察不同浓度乳酸状态下对骨骼肌力学的影响.取小鼠腹直肌条,为防止热缺血缺氧性损伤,先采用预冷灌流液处理,再缓慢复温,把小鼠腹直肌一端固定在恒温肌槽中,另一端连接张力换能器,采用生物机能实验系统,分别记录分析0 mmol,2 mmol,4 mmol,8 mmol,16 mmol/L等乳酸浓度下的腹直肌条接受电刺激(电刺激强度为1.2倍最大刺激强度)后力学的变化.在不同乳酸浓度下,肌肉收缩时张力变化不明显(P>0.05),但肌肉收缩和舒张时的张力速率随着乳酸浓度的增高呈直线关系.不同乳酸浓度组之间的dF/dt和-dF/dt的比较存在着显著性的差异(P<0.01或P<0.05).提示运动时产生的乳酸对肌肉收缩力学的影响主要降低dF/dt和-dF/dt,可能是造成肌肉做功能力降低的重要因素.

Effect of the Different Lactic Acid Concentration on Mechanics Change of Skeletal Muscle

The purpose of the study is to observe the effect on the mechanics change of skeletal muscle in the state of different lactic acid concentration.To prevent the muscle slip which was cliped from the belly of rat from being damaged by blood deficiency and oxygen deficiency in heat,it was cooled by the precooled flowing liquid first,then regained its former temperature slowly.one end of the muscle slip was fixed in constant temperature sank,and the other is linked with the transducer of tension.By the experiment system of biological function.The mechanics change of skeletal muscle was recorded after electrical stimulation(the max strength of the electrical stimulation is 1.2 times) in the different lactic acid density(0 mmol,2 mmol,4 mmol,8 mmol,16 mmol/L,and so on).the change of muscle tension is not so obvious when it systoles(P>0.05),but the tension velocity increased when muscle systoles and diastoles with the increasing lactic acid concentration.The result showed a straight line relativity.The dF/dt and-dF/dt among the different lactic acid concentration groups were of great difference(P<0.01 or P<0.05).So it indicated that the lactic acid produced in sports would mainly decrease the dF/dt and-dF/dt of muscles systole.It may be an important factor to result in lowering the ability of muscle work.