[Mechanisms of suppression of physiological function in hypothermia and a way of their restoration without body warming].

It was shown that in hypothermic rats (rectal temperature 25-22 degrees C) it was possible to stimulate responses that had been suppressed by cold (i. e. thermoregulation and breathing) with the aid of injecting a solution of ethylenediaminetetraacetic acid disodium salt (EDTA) in quantity 16.5 mg/100 g of body weight (0.0045 mmol/100 g) into the blood stream of the cooled animals. EDTA connects calcium ions in blood and forms complexes. It was shown that enhancement of cold shivering intensity and that of breathing (in 5 min after beginning the injection of EDTA) coincided with a 42-45 % reduction of [Ca2+] in the blood]. After 15 min following the beginning of injection of EDTA [Ca2+] into the blood stream, a return to the initial level was observed in cooled animals. Simultaneously we observed suppression of the cold shivering and breathing. The repeated injection of EDTA again caused similar fall of [Ca2+] in the blood and the following enhancement of cold shivering and breathing.