Effect of intracellular pH on force and heat production in isometric contraction of frog muscle fibres.
Effect of intracellular pH on force and heat production in isometric contraction of frog muscle fibres.
复制标题
细胞内 pH 值对青蛙肌肉纤维等长收缩力和产热的影响。
DOI：
10.1113/jphysiol.1988.sp016952
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发表时间：
1988
期刊：
影响因子：
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通讯作者：
R. Woledge
中科院分区：
文献类型：
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作者：
N. Curtin;K. Kometani;R. Woledge
1.在10 ℃下（使用pH敏感微电极），在含有固定碳酸氢盐浓度（20 mM）和不同PCO 2浓度（0.5 - 54%）的林格氏溶液中，测量青蛙蛙胫骨前肌活纤维的细胞内pH值（pHi）。随着细胞外pH从7.99变为6.00，平均pHi从7.24变为5.97。在20 ℃下获得类似的结果。2.在平行实验中，测量了在10 ° C下4秒等长强直中的力和产热速率，并与对照观察结果（5%CO2，pHi 6.80）进行了比较。3.随着纤维变得更酸（pHi 5.95），力和热速率逐渐降低（分别为对照值的0.75和0.71）。4.随着纤维变得更碱性（至pHi 7.26），力略微增加（最大为对照值的0.03），但热速率没有增加。5.当考虑磷酸肌酸分解的摩尔焓变对pH的依赖性时，这些结果表明，在此范围内，每个跨桥循环的力-时间积分随pHi增加。
1. The intracellular pH (pHi) of live fibres from the anterior tibialis of the frog Rana temporaria was measured at 10 degrees C (using pH‐sensitive microelectrodes) in Ringer solutions containing a fixed bicarbonate concentration (20 mM) and varying PCO2 concentrations of 0.5‐54%. As extracellular pH was changed from 7.99 to 6.00, mean pHi changed from 7.24 to 5.97. Similar results were obtained at 20 degrees C. 2. In parallel experiments force and rate of heat production in 4 s isometric tetani at 10 degrees C were measured, and compared to control observations (5% CO2, pHi 6.80). 3. As the fibres became more acid (to pHi 5.95), force and heat rate were progressively reduced (to 0.75 and 0.71 of the control values, respectively). 4. As the fibres became more alkaline (to pHi 7.26), force increased slightly (by a maximum of 0.03 of the control value) but heat rate did not increase. 5. When the dependence on pH of the molar enthalpy change for phosphocreatine splitting is taken into account, these results indicate that the force‐time integral per cross‐bridge cycle increases with pHi over this range.