The relation of water, sodium, and potassium distribution to work performance in old rats.
The relation of water, sodium, and potassium distribution to work performance in old rats.
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老年大鼠水、钠、钾分布与工作表现的关系。
DOI：
10.1159/000211175
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发表时间：
1963
期刊：
影响因子：
--
通讯作者：
S. Friedman
中科院分区：
文献类型：
--
作者：
F. Sréter;S. Friedman
方法雄性白化病大鼠20只，年龄5 ~ 7月龄，20 ~ 25月龄。麻醉和分析方法同前1.在菊粉平衡2小时后切除右侧胃肌以测量基础值，暴露左侧腓肠肌，将其肌腱与比目鱼肌小心分离，远端绑在一起，然后在接近其与跟腱的连接处切断。分离左侧坐骨神经进行刺激，并通过穿过股骨钻孔下端的针牢固固定左腿进行等长记录。然后将腓肠肌的游离远端连接到Grass力-位移传感器（FT 03），通过Grass多导生理记录仪进行记录。校准传感器，以建立施加到仪器的力（g）与记录笔偏转之间的十进制关系。在运动期之前，通过确定在肌肉长度增加mm的范围内对单次抽搐的反应来估计用于工作的肌肉的最佳长度。然后将肌肉固定在其最佳长度，并使用Grass刺激器（S 4）提供的持续时间为0.2毫秒的方波脉冲和超大强度以10/秒的速率间接刺激。电活动的刺激肌肉的机械反应的同时记录的两个粗壮的衣领的棉絮浸泡在林格溶液和放置在肌肉表面上，一个在肌腱端，另一个更近端的肌腹。这些电极通过肌电图仪（EMG）连接到多导生理记录仪。刺激20分钟后，通过颈动脉插管采集第二份血样，并切除整个左腓肠肌，如前所述进行分析。由于比目鱼肌是一种缓慢的肌肉，其水和离子分布与腓肠肌不同，因此总是小心地排除。
MethodsTwenty young and 28 old male albino rats of an inbred Wistar strain, 5 to 7 and 20 to 25 months of age respectively, were used in this experiment. Anesthesia and analytic methods were as before1.Following excision of the right gastroncemius for measurement of basal values after 2 hours of inulin equilibration, the left gastrocnemius was exposed and its tendons, carefully separated from soleus, were tied together distally and then cut free close to their insertion into the common Achilles tendon. The left sciatic nerve was isolated for stimulation and the left leg firmly fixed for isometric recording by a needle passed through the drilled lower end of the femur. The free distal end of the gastrocnemius was then connected to a Grass force-displacement transducer (FT 03) recording through a Grass Polygraph. The transducer was calibrated to set up a decimal scale relation between force in g applied to the instrument and the deflection of the recording pen. The optimal length of the muscle for work was estimated before the exercise period by deter mining the response to single twitches over a range of mm increases in muscle length. The muscle was then fixed at its optimal length and stimulated indirectly at a rate of 10/sec using square wave pulses of 0.2 millisec duration and supramaximal intensity delivered from a Grass stimulator (S 4). Electrical activity of the stimulated muscle was recorded simultaneously with its mechanical response by means of two stout collars of cotton wool soaked in Ringer solution and placed on the muscle surface, one at the tendinous end, the other more proximally on the muscle belly. These electrodes were connected to the Polygraph through an electromyograph (EMG) preamplifier. After 20 minutes of stimulation a second blood sample was taken through the carotid cannula and the whole left gastrocnemius excised and anlyzed as before. Because soleus is a slow muscle with a water and ionic distribution different to that of gastroc nemius it was always carefully excluded.