[Characteristics of energy metabolism in the myocardium under artificial hypothermia]

The effect of cooling and subsequent rewarming on the tissue respiration of canine hearts was studied during polycomponent ether-oxygen anaesthesia. The tests included the determinations of the activity of the dehydrogenases of the cytrate cycle, the content and activity of chromoproteids, the respiration rate of the mitochondrias on succinate, glutamate and ketoglutarate, the content of glycogen, the activity of the phosphorylases, hexokinase, lactate dehydrogenase, the content of lactate, pyruvate, adenyl nucleotides and creatine phosphate. Significant changes were noted in the content and activity of the above substances, acceleration of mitochondrial respiration, reduced energy regulation of respiration, and decreased amount of the adenyl components. It is suggested that under artificial hypothermia the processes of chromoproteids biosynthesis are enhanced, which results in an increased power of terminal respiration, and conformational rearaangements of the enzymes connected with the membranes occur.