Comparative response of 2-week and 6-month old rat myocardium to hypoxia.
Comparative response of 2-week and 6-month old rat myocardium to hypoxia.
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2周和6月龄大鼠心肌对缺氧的反应比较。
DOI：
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发表时间：
1985
期刊：
影响因子：
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通讯作者：
O. H. Bing
中科院分区：
文献类型：
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作者：
W. W. Brooks;B. Ekblom;O. H. Bing
本文观察了缺氧对2周龄和6月龄大鼠左室乳头肌收缩功能的影响。左心室糖原浓度在2周龄和6月龄心脏之间没有显著差异;然而，2周龄大鼠左心室心肌的乳酸脱氢酶同工酶谱显示出相对于6月龄动物向M型（厌氧）分布的转变。在28 ° C下研究了乳头肌的性能，同时在氧合环境中在主动张力曲线的峰值处收缩12次/分钟。（95%氧气，5%二氧化碳）含葡萄糖浓度为5.5至22 mM的Krebs-Henseleit溶液。在含5.5 mM葡萄糖的浴中，缺氧期间产生的张力下降（95%氮气，5%二氧化碳）的2周龄大鼠的制剂中，（P <0.05）比6-将浴中的葡萄糖浓度提高到11和16.5 mM导致在整个60 min缺氧期间性能的改善，与6月龄动物相比，2周龄动物的制备物。心得洛尔（5 × 10（-5）M）不能阻止在2周动物制备物中观察到的耐缺氧性增加。因此，增加厌氧底物对缺氧2周和6个月心肌的性能有不同的影响。这些数据表明，在对比6个月大的心肌，心肌从2周龄的大鼠是能够调节其积极的机械活动在缺氧期间根据糖酵解底物的可用性。
The effect of hypoxia on contractile performance of left ventricular papillary muscles from 2-week old and 6-month old rats was studied. Left ventricular glycogen concentration was not significantly different between 2-week and 6-month old hearts; however, the lactate dehydrogenase isoenzyme pattern of the left ventricular myocardium from the 2-week old rats demonstrated a shift toward M-type (anaerobic) distribution relative to 6-month-old animals. Papillary muscle performance was studied at 28 degrees C while contracting 12 times/min at the peak of the active tension curve in oxygenated (95% oxygen, 5% carbon dioxide) Krebs-Henseleit solution containing glucose concentrations from 5.5 to 22 mM. In a bath containing 5.5 mM glucose, the decline in developed tension during hypoxia (95% nitrogen, 5% carbon dioxide) of preparations from the 2-week old rats was significantly less (P less than 0.05) than the 6-month old group only at 15 min. Raising the glucose concentrations of the bath to 11 and 16.5 mM resulted in improved performance throughout 60 min of hypoxia in preparations from 2-week compared with 6-month old animals. Practolol (5 X 10(-5)M) did not prevent the increased tolerance to hypoxia observed in preparations from 2-week animals. Thus, increasing anaerobic substrate has differential effects on the performance of 2-week and 6-month myocardium during hypoxia. The data suggests that in contrast to 6-month old heart muscle, myocardium from 2-week old rats is capable of modulating its active mechanical activity during hypoxia in accordance with the availability of glycolyptic substrate.