Key result
Cooling rat muscles below 20°C resulted in a marked depression of tetanic tension, with activation energy estimates below 21°C being twice as high as those above 24°C.
Why the study?
Does temperature variation affect tetanic tension development in rat fast-twitch and slow-twitch muscles?
Does temperature variation affect tetanic tension development in rat fast-twitch and slow-twitch muscles?
Cooling below 25 degrees C significantly depresses tetanic tension and alters the temperature dependence of tension development and relaxation in rat skeletal muscle.
Cautions against direct clinical extrapolation from rat models; leaves open human muscle temperature effects pending further study.
The effect of temperature on tetanic tension development was examined in extensor digitorum longus (fast-twitch) and soleus (slow-twitch) muscles of the rat, in vitro and with direct stimulation. The temperature range was from 35 to 10 degrees C. 2. The maximum tetanic tension decreased slightly on cooling from 35 to 25 degrees C. Cooling below 20 degrees C resulted in a marked depression of tetanic tension. The results were similar in the two muscles. 3. Analysis (in the form of Arrhenius plots) of the rate of tetanic tension development and relaxation clearly showed the occurrence of two phases in their temperature dependence, due to an increased temperature sensitivity below about 25 degrees C. Arrhenius activation energy estimates for temperatures lower than 21 degrees C were around twice as high as those for temperatures higher than 24 degrees C in both muscles.
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Ranatunga et al. (1983) studied Normal rat muscle physiology. Temperature reduction was evaluated on Tetanic tension development and relaxation. Cooling rat muscles below 20°C resulted in a marked depression of tetanic tension, with activation energy estimates below 21°C being twice as high as those above 24°C.
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