[Morphologic basis for several myocardial metabolic disorders in the presence of respiration uncoupled from phosphorylation]

It was experimentally established that the destruction of mitochondria due to a reduction of ATP production and to their compensatory hyperfunction under energy defecit is underlying some disorders in the myocardial metabolism caused by 2,4-DNP intoxication. Energy deficit results in K+ metabolism disorders and the related acetylcholine synthesis which predisopses the changes in the cardiac function and still further increases the myocardial requirements of energy. The bio-energy disorders develop in a vicious circle manner, and when the intoxication increases, it inevitably results in energy depletion and cardiac arrest.

[Role of mitochondrial swelling in the energetic effectiveness of intact myocardial cells (according to electron microscopy data)]

The myocardium of the left and the right cardiac ventricles was studied at various seasons on 20 rabbits. There was found a distinct seasonal dynamics of a number of quantitative indices of electronograms. In particular, there was found a relationship between the coefficients of energy efficacy of the mitochondria (integral value--calculated by multiplying the mitochondrial area by the number of mitochondrial cristae) and the mitochondrial area. With increase of the latter to 0,85 mc2 this relationship is positive and linear. With further swelling of the mitochondria this relationship disappears, however.

[Effect of large doses of nicotinic acid on certain metabolic processes and contractile function of an intact heart]

Peroral administration of nicotinic acid to rabbits in amounts of 500 mg, twice a day for 7 days was attended by a reduced contractility of the myocardium, an increased content of catecholamines in the heart and deranged lipids metabolism in the heart muscle. It is assumed that the contractility of the heart is largely determined by the state of the lipids metabolism and their utilization in the generation of energy.