Changes of activity of the protein-synthesizing system of brain neurons of the ground squirrel Citellus undulatus during hibernation and hypothermia

Using fluorescent and electron microscopy a comparative analysis was performed of components of the protein-synthesizing system of hippocampal neurons both in ground squirrels in various phases of the torpor-activity cycle and in rats cooled under the hypoxia-hypercapnia conditions. Results of the study have shown that in hippocampal neurons of the ground squirrels entering the natural torpor state and of rats under conditions of artificial hypothermia to 17°C, similar mechanisms might be possible to function, one of their obligatory components being a generalized decrease of activity of the protein-synthesizing system with its subsequent restoration at the exit from hypothermia. Cessation of hypoxia-hypercapnia even under conditions of a further temperature decrease restored the rat neuronal protein-synthesizing activity, which seems to indicate the presence of a potential possibility of adaptation of brain neurons in vivo to low temperatures, at which the integral organism of non-hibernating homoeothermic animals does not survive.[PUBLICATION ABSTRACT]