[Cardioprotective effect of energostim in toxic allergic myocarditis]. / Kardioprotektornoe deistvie énergostima pri toksiko-allergicheskom miokardite.

Energostim is a combined drug comprising a mixture of nicotinamide adenine dinucleotide (0.5 mg), cytochrome C (10 mg), and inosine (80 mg), representing antihypoxant and antioxidant of direct action in one ampule. After pretreatment and subsequent 3-day energostim therapy of animals with 3-day toxico-allergic myocarditis (3d-TAM), the ECG was free of any rhythm disorders and showed evidence of improved conduction, restoration of the normal form of T-wave and the position of ST segment, while the content of myofibrillar fraction of creatine phosphokinase and toxic products of disturbed metabolism (degree of endotoxemia) decreased to the upper normal level. Under the action of energostim, neither pressure nor the maximum rate of pressure buildup in the left ventricle are reduced (as they do upon 3d-TAM); neither systolic and diastolic functions are disturbed, nor their coordination (r = 0.79 between dP/dtmin and dP/dtmax, p < 0.01). The restoration of contractile activity and maximum rate of relaxation of myocardial microfibrils during 3d-TAM is accompanied by an increase in the content of adenyl nucleotides, in the ATP/ADP, ADP/AMP, NAD/NADH, and NADP/NADPH ratios, and in the cytosol phosphorylation potential. The energostim-induced improvement in the energy supply system are accompanied by restoration of the ability of sarcoplasmic reticulum to efflux Ca2+. Thus, it is demonstrated that the effect of energostim is related to its ability to actively participate in intracell metabolic processes in myocardium, abolish necrotic changes and endotoxicosis, and restore homeostasis in the systems responsible for the contraction--relaxation process (thus preventing from the development of dysfunction of the left ventricle and the heart failure).

[The comparative efficacy and differences in the molecular mechanism of the inotropic action of cardiac glycosides and nonglycoside cardiotropic agents on the contractile protein system of the myocardium]. / Sravnitel'naia éffektivnost' i razlichiia v molekuliarnom mekhanizme inotropnogo deistviia nekotorykh serdechnykh glikozidov i neglikozidnykh kardiotropnykh sredstv na sistemu kontraktil'nykh belkov miokarda.

The in vitro study on an isolated system of myocardial contractile proteins determined optimal concentrations of the positive inotropic action and biological activity ranges of beta-methyldigoxin (beta-MD), strophanthin K, K-strophantozide, beta-acetyldigoxin (beta-AD), milrinone, and amrinone. Optimal concentrations of the beta-MD and strophanthin K (10(-2) and 10(-6) M, respectively) significantly increased qualitatively and quantitatively the economy and thermodynamic efficiency, altered the energy transformation in the contractile protein system under the isometric contraction, whereas the beta-AD produced only the quantitative effect. However, the beta-MD and strophanthin K at concentrations exceeding the optimal one by one order lost the ability to produce the qualitative effect, retaining only the quantitative one in the actomyosin ensemble. The strophanthin K significantly increased the economy of a single actomyosin ensemble in the force generation phase and the beta-MD in the tension maintenance phase. Unlike the strophanthin K, the beta-MD did not slow down (did not worsen) the relaxation process. This provides grounds to conclude that the beta-MD produces most favorable effect on the energy transformation by myocardial contractile proteins.