| Abstract: | A study was made of the dynamics of seasonal changes in heat resistance of the organism and muscles of the green toad taken from micropopulation living in the North-Eastern suburbs of Tashkent. The heat resistance of the organism was determined by the time of onset of the irreversible heat shock caused by the immersion of animals into water at 39 +/- 0.1 degrees C. The heat resistance of muscles (m. gastrocnemius) was determined by the time of the loss of response to electrical stimulus during heating in the Ringer solution (41 +/- 0.1 degrees). It has been shown that the organism as a whole is much more dependent on seasonal variations of environmental temperature as compared with muscle tissue. Of much importance for the changes in the heat resistance of muscle tissue are cyclic hormonal changes in the organism associated with the process of reproduction and preparation to it. |
