[Glucose-6-phosphate dehydrogenase in rat liver and myocardium following toxic doses of noradrenaline]

Administration of toxic doses of noradrenaline into rats led to exhaustion of noradrenaline reserves in liver and heart tissues with the simultaneous increase in the activity of glucose-6-phosphate dehydrogenase in the tissues. Actinomycin D, administered together with noradrenaline, completely prevented the elevation of the G6PD activity in the tissues studied. The data obtained suggest that sympathetic nervous system and its mediator are responsible for regulation of the rate of enzymatic protein synthesis in tissues.

[Comparison of the contractile function of the heart in hares and rabbits under conditions of relative rest and under resistance loading]

A comparison was conducted between the contractile function of the heart of hares and rabbits at rest and under isometric contractions regimens, and under such conditions the concentration of ATP and its breakdown products was studied in the myocardium of both species. It was demonstrated that the cardiac muscle of hares adapted by the evolution to the performance of intensive work does not possess any increased ability of developing systolic tensions, or any increased power of the ATP resynthesis apparatus. The advantage of such a heart-- its ability to pump an increased blood volume -- must be ensured by some different mechanism that requires still further investigations.

[Activity of various enzymes of energy metabolism of the myocardium after neurogenic injury]

A 3-hour electrostimulation of the aortic arch in rabbits was followed by the exhastion of the tissue noradrenaline stores in the myocardium accompanied by increase in the activity of the glycolysis enzymes and of the enzyme limiting the process of the pentosophosphate route-G-6-PDH. The use of noradrenaline precursor - 1-DOPA restored the noradrenaline level in the myocardium completely after a 48-hour stimulation. Simultaneously there were noted no changes in the activity of the enzymes under study caused by the stimulation of the aortic arch. The data obtained confirmed the important role of the sympathetic nervous system and of its mediator - noradrenaline in the mechanism of the tissue metabolism regulation, whose derangement played a significant role in the development of dystrophic lesions of the heart tissue.

[Energy metabolism and myocardial function in myocardiodystrophy]

A total of 92 patients with chronic tonsilitis and cardiovascular changes were subjected to clinical observations, ECG analysis, potassium and nitroglycerine tests, and studies of the lactic acid level and creatinekinase activity as indces of myocardial metabolism. The examinations were conducted prior to and following tonsillectomy. In a majority of patients a correlation was revealed between the degree of ECG changes and the serum lactic acid level, as well as between the ECG improvement and a reduction of the lactic acid level following tonsillectomy. Three stages of tonsillogenic myocardiodystrophy were distinguished. The obtained data indicate the rationale of the used tests for the evaluation of the myocardial meabolism alterations and of the efficacy of treatment of chronic tonsillitis patients.

[Activity of energy metabolism related enzymes in the myocardium and liver following administration of large doses of noradrenaline]

The activity of the glycolytic enzymes and of the glucose-6-phosphate dehydrogenase (G-6-PDH) were compared with the content of noradrenaline in rat myocardium and the liver after the intraperitoneal injection of high doses of noradrenaline. It was shown that 24 hours after int noradrenaline injection which caused exhaustion of endogenous catecholamine supply, the lactate content and the activities of lactic dehydrogenase were increased in the myocardium; the activity of hexokinase and G-6-PDH in rat myocardium and the liver were also increased, whereas the glucokinase activity was decreased. In these experiments alterations of the enzyme activities were shown to be similar to the alterations in the dystrophic tissues in which the catecholamine content was sharply decreased. The role of the sympathetic nervous system and its mediators in the mechanism of the enzyme regulation of the energy metabolism in the myocardium and the liver is discussed.

[Prophylactic and therapeutic action of etimizol on the change in myocardial tissue metabolism in a neurogenic lesion]

The effect of aethimizol, introduced to rabbits before and after inflicting a 3-hours long extraordinary stimulation applied to the reflexogenic zone of the aortic arch, was studied. Investigations covered some aspects of energy metabolism and the level of the norepinephrine mediator in the muscle of the heart and also the functional state of the latter. Aethimizol was found to prevent shifts of the studied metabolic factors, induced by electric stimulation, and also to avert depletion of norepinephrine in the tissue of the myocardium and normalize its function.