论文部分内容阅读
目的本实验拟建立测量骨骼肌肌质网(SR)钙离子释放功能的简便方法。方法分析大鼠离体比目鱼肌肌条间断强直收缩张力峰值到75%恢复的时间(TR75),TR75呈先延长然后缓慢缩短。以延长至最大时的TR75除以第一次强直收缩的TR75,获得TR75延长比值(R-TR75)。结果增加刺激电压或用5mmoL/L Caffeine灌流(增加SR Ca2+释放通道开放几率)比目鱼肌肌条,R-TR75从对照组的2.5倍均增加到3.0倍。相反,5 mmol/L硫酸镁灌流抑制SR Ca2+释放通道,使R-TR75明显减小。间隔60 min的2次间断强直疲劳收缩,其R-TR75间无明显差别,但间隔5或10 min,再次进行间断强直疲劳收缩期间的R-TR75呈显著减小。萎缩比目鱼肌间断强直疲劳收缩期间,R-TR75增加2.9倍,明显高于对照组。结论比目鱼肌肌条间断强直疲劳收缩期间,在肌质网Ca2+-ATP酶活性没有改变的条件下,TR75延长比值可间接反映SR钙释放功能。另外,去负荷2周萎缩比目鱼肌的R-TR75增加提示其SR钙释放功能可能增强。
Objective This experiment intends to establish a simple method for measuring the release of calcium ions from skeletal muscle sarcoplasmic reticulum (SR). Methods The time to recovery (75%) of the tetanic contractile tension in isolated soleus muscle strips of rats was observed. TR75 was first prolonged and then shortened. The TR75 extension ratio (R-TR75) was obtained with TR75 extending to the maximum divided by the first tonic contraction of TR75. Results Stimulation of voltage or perfusion with 5mmoL / L Caffeine (increased SR Ca2 + release channel opening probability) soleus muscle strips, R-TR75 increased from 2.5 times the control group to 3.0 times. In contrast, 5 mmol / L magnesium sulfate inhibited the release of SR Ca2 + channels and markedly decreased R-TR75. There was no significant difference in R-TR75 between the two intermittent anastomotic contractions 60 min apart. However, R-TR75 was significantly reduced during intermittent tetanic fatigue and contractions after an interval of 5 or 10 min. R-TR75 increased 2.9-fold during atrophy of the contralateral soleus during atrial fibrillation, which was significantly higher than that of the control group. CONCLUSIONS: The ratio of prolongation of TR75 indirectly reflects SR Ca2 + release function under the condition of no change of sarcoplasmic reticulum Ca2 + -ATPase during intermittent tetanus and fatigue contraction of soleus muscle strips. In addition, an increase in R-TR75 in the soleus muscle during 2 weeks of detrusor loading suggests that SR calcium release may be enhanced.