[Activity of oxidative enzymes of the Krebs cycle in the brain of animals adapted to supercooling].

Multiple (15-17) coolings up to the rectal body temperature (19-20 degrees C) without application of narcotic substances bring about various changes in the activity of the rat brain tricarboxylic acid cycle dehydrogenases: the activity of malate, succinate and alpha-ketoglutarate dehydrogenases increases significantly, that of isocitrate dehydrogenase decreases, that of pyruvate dehydrogenase--remains unchanged. The reaction to cooling in animals adapted to supercooling is also specific: in rats cooled for the first time in the state of "cold narcosis" succinic acid is mainly consumed in the brain, and in the adapted rats cooled down to 19-20 degrees C alpha-ketoglutarate dehydrogenase plays an important role.