Oxygen consumption of single muscle fibres of Rana temporaria and Xenopus laevis at 20 degrees C.
Oxygen consumption of single muscle fibres of Rana temporaria and Xenopus laevis at 20 degrees C.
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20℃下林蛙和非洲爪蟾单肌纤维的耗氧量。
DOI：
10.1113/jphysiol.1988.sp017088
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
W. J. van der Laarse
中科院分区：
文献类型：
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作者：
G. Elzinga;W. J. van der Laarse
1.在20 ℃条件下，研究了蛙和非洲爪蟾单根肌纤维收缩时的耗氧量。2.将蛙的胫骨前肌和爪蟾的髂腓肌的单纤维安装在含有林格氏溶液的室中。搅拌该溶液，用极谱法连续测定其氧分压（PO 2）。3.单根纤维的稳态耗氧率（VO 2）被确定为抽搐频率的函数（0.2 - 12刺激s-1，取决于纤维的类型）。VO 2随颤搐频率增加而增加，直至达到平台值（VO 2，max）。不同纤维的VO 2，max在蛙中为0.042至0.169 nmol O2 s-1 mg-1干重，在爪蟾中为0.045至0.412 nmol O2 s-1 mg-1干重。在VO 2、最大氧利用率条件下，氧利用率不是限制因素。4.将解偶联剂羰基氰化物间氯苯腙（CCCP）注入腔室后的VO 2与VO 2，max相关，表明VO 2，max由线粒体密度决定。这一建议得到证实的观察，VO 2，最大值和琥珀酸脱氢酶活性之间存在着密切的关系，在三种不同的纤维类型的爪蟾。5.在VO 2，max时，大多数纤维在颤搐训练后吸收了大量的氧，这表明氧化ATP合成不能与ATP水解相匹配。具有高氧化能力的爪蟾肌纤维没有表现出这种现象。6.结果进行了讨论，在肌纤维中的缺氧核心的发生和最大的稳态收缩活动可达到的纤维。
1. Oxygen consumption of contracting single muscle fibres of Rana temporaria and Xenopus laevis was investigated at 20 degrees C. 2. Single fibres of the tibialis anterior muscle of Rana and the iliofibularis muscle of Xenopus were mounted in a chamber containing Ringer solution. The solution was stirred and its partial pressure of oxygen (PO2) was continuously measured polarographically. 3. Steady‐state rates of oxygen consumption (VO2) of single fibres were determined as a function of twitch frequency (0.2‐12 stimuli s‐1, depending on the type of fibre). VO2 increased with twitch frequency until a plateau value (VO2,max) was reached. VO2,max of different fibres ranged from 0.042 to 0.169 nmol O2 s‐1 mg‐1 dry weight in Rana and from 0.045 to 0.412 nmol O2 s‐1 mg‐1 dry weight in Xenopus. Under VO2,max conditions oxygen availability was not the limiting factor. 4. VO2 after injection of the uncoupler carbonyl cyanide m‐chlorophenylhydrazone (CCCP) into the chamber correlated with VO2,max, suggesting that VO2,max is determined by mitochondrial density. This suggestion was confirmed by the observation that a close relationship exists between VO2,max and succinate dehydrogenase activity in three different fibre types of Xenopus. 5. At VO2,max a considerable amount of oxygen was taken up after the twitch train by most fibres, indicating that the oxidative ATP synthesis cannot match ATP hydrolysis. Xenopus muscle fibres with high oxidative capacity did not show this phenomenon. 6. The results are discussed in relation to the occurrence of anoxic cores in muscle fibres and the maximum steady‐state contractile activity attainable by the fibres.