The effect of swimming instantly following an injection of isoproterenol was studied in rats in whom the administration of the drug caused changes in the cardiac muscle. The animals were compared with those of a group kept only under normal cage activity after the administration. Oxygen inhalation in the exercised group of rats was higher than in the sedentary group and after 4 minutes of measuring, continually remained at a higher level. It was determined that swimming prevented the early death of the rats. This was more pronounced in the animals of higher body weight. The extent of myocardial damage in the exercised group was markedly smaller. The intensity of enzyme reaction, SDH, LDH and G6PDH, in the area of undamaged tissue was the same in both the exercised and sedentary groups, in areas of damage it was minimal. The intensity of alpha GP was lowered in the exercised group, but in the sedentary group it was lowered throughout the entire section. Electron optic examination of the tissue, which under the light microscope appeared normal, revealed no substantial differences between the exercised and sedentary groups. We presume that the better condition of the rats was in part due to the peripheral breakdown of the catecholamine owing to the increased blood flow created by muscular activity.

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PubMedDate not supplied

Suppression of the progress of necrosis after coronary artery ligation in the dog by pharmacologic interventions.

A study was carried out of a therapy supporting the anaerobic glycolysis and coronary perfusion of ischemic myocardium and preserving its potassium and magnesium contents, which consisted in combined administration of hyaluronidase, glucose, insulin, Tris, methoxamine, and potassium and magnesium aspartate. The drugs were administered to Beagle dogs between 30 minutes and 20 hours after the ligation of the left anterior descending coronary artery. The size of infarction was determined by the Nachlas method, which is based on the detection of activities of dehydrogenases in heart slices. Treated animals showed a reduced infarction size (p less than 0.001). The evidence of the favourable effect of the therapy used was brought also by hemodynamic measurements. The heart rate was slower (p less than 0.02) and the mean arterial blood pressure was higher (p less than 0.001) in treated animals than in control ones (as evaluated at the end of the experimental period). Significant correlation between the infarction size and the heart rate on the one hand and the mean arterial pressure on the other hand was found (r = 0.59, p less than 0.01; r=--0.47, p less than 0.05, respectively).

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