[Temperature dependence of the heat of activation in a single isometric contraction of the rat diaphragm. The effect of extra- and intracellular temperature].

Using a myothermometric method it was found that at 27 degrees and 37 degrees C the activation heat (Qa) of a single isometric contraction of the Wistar's rats isolated diaphragm averages 0.26 +/- 0.02 mcal/g and 0.60 +/- 0.13 mcal/g, accordingly, and Q10 = 2.3. It has been proved that the value of Qa depends on the gradient of intracellular temperature decrease (delta T, r = 0.89, p less than or equal to 0.01) as Qa = 1.68 delta T + 1.30 under 0.01 less than or equal to delta T less than or equal to 1.0. It was concluded that high significance of Qa for the muscles of warm-blooded points to the damaged energetics of the contraction recovery period and delta T is an intracellular informative signal which always determines the value of Qa via the feedback mechanism.