[The action of sodium oxybutyrate and emoxypin on the functional state of the adrenaline-damaged myocardium in an experiment]. / Deistvie natriia oksibutirata i émoksipina na funktsionnal'noe sostoianie povrezhdennogo adrenalinom miokarda v éksperimente.

The effect of agents possessing antihypoxic and antioxidant activity, namely sodium oxybutyrate and emoxypin, on the functional state of the heart muscle was studied in experiments on dogs with epinephrine necroses of the myocardium. A marked cardioprotective effect was produced by sodium oxybutyrate infused intravenously (200 mg/kg) either 10 min or 2 hrs after myocardial damage had been modelled and by emoxypin (4 mg/kg; 0.4 mg/kg) infused intravenously 30 min after the damage.

[The current possibilities for the pharmacological regulation of myocardial metabolism in experimental catecholamine-induced necroses]. / Sovremennye vozmozhnosti farmakologicheskoi reguliatsii metabolizma miokarda pri éksperimental'nykh katekholaminovykh nekrozakh.

Catecholamine-induced myocardial necroses have their own peculiarities but the disorders in myocardial metabolism occurring in them do not differ in quality from those encountered in necroses caused by occlusion of the coronaries. Pharmacological regulation of the metabolism of a myocardium damaged by catecholamines may be accomplished by the same drugs which are used in necroses caused by coronary occlusion, but agents with antihypoxic and antioxidant activity are preferable.

[Action of dopamine on glucose level and glycogen phosphorylase activity of blood plasma in experimental coronary occlusion]. / Deistvie dofamina na uroven' gliukozy i glikogenfosforilaznuiu aktivnost' plazmy krovi pri éksperimental'noi koronarookkliuzii.

The effects of dopamine (5 micrograms/kg.min) on the blood plasma glucose level and glycogen-phosphorylase activity in experimental coronary occlusion were studied. The absence of the raising of the plasma glucose level and glycogen-phosphorylase "a" and "b" activities has been observed in 25 min after the coronary occlusion. It is supposed that the functional improvement of the ischemized myocardium by dopamine (5 micrograms/kg.min) is the result of the stimulation of presynaptic D-2-dopaminergic and postsynaptic D-1-dopaminergic receptors in coronary arteries.

[The effect of propranolol and flusoxolol on the lysosomal enzyme activity of the rat ventricular myocardium]. / Vliianie propranolola i fluzoksolola na aktivnost' lizosomal'nykh fermentov miokarda zheludochkov krys.

The nonselective beta-blocker propranolol and the selective beta 1-adrenoblocker flusoxolol were tested for their effects on the activities of acid phosphatase, acid DNAase, cathepsin D, beta-glucosidase and beta-galactosidase in intact rat ventricular myocardial homogenates. The two drugs were found to have the most noticeable effect on the activity of three enzymes under study: acid phosphatase, beta-glucosidase and beta-galactosidase. They were able to stabilize lysosomal membranes during long-term homogenate preincubation at 37 degrees S. It is suggested that the mechanism of action of the drugs on intact rat ventricular myocardial lysosomes under the conditions of the study involves the binding of both propranolol and flusoxolol to beta-adrenoceptors on the lysosomes.

[The effect of practolol and atenolol on the lysosomal enzyme activity of the ventricular myocardium of rats]. / Vliianie praktolola i atenolola na aktivnost' lizosomal'nykh fermentov miokarda zheludochkov krys.

The influence of cardioselective beta-blockers, practolol and atenolol, on acid phosphatase, acid deoxyribonuclease, cathepsin D, beta-glucosidase and beta-galactosidase activities was studied in homogenates of intact rat ventricular myocardium. In the presence of drugs (1 x 10(-9)-1 x 10(-5) M) the activities of acid phosphatase, cathepsin D, beta-glucosidase and beta-galactosidase tended to diminish but the activity of acid deoxyribonuclease tended to increase. Some differences in the influence of drugs on the enzyme activities were removed by prolongation of preincubation of homogenates with drugs. It is supposed that the mechanism of influence of beta-blockers on lysosomes of the intact rat ventricular myocardium in conditions of this study includes the specific drug binding to beta-adrenergic receptors situated on lysosomes.

[The effect of adrenergic agents on the level of extracellular potassium normally and in myocardial ischemia (infarct)]. / Vliianie adrenergicheskikh sredstv na uroven' vnekletochnogo kaliia v norme i pri ishemii (infarkte) miokarda.

Adrenergic drugs exert effects on the processes of potassium ions transmembrane distribution between the intra- and extracellular spaces. Drug-induced hypokalemia is the result of beta (predominantly beta-2) adrenergic stimulation. Arrhythmias in myocardial ischemia occur at the combination of hypercatecholaminemia and rapid transmembrane distribution of potassium ions between the intra- and extracellular spaces. The distribution results in the association of the increased local extracellular potassium concentration in the myocardium and rapidly developing hypokalemia.

[The effect of dopamine on the systemic hemodynamic indices, on the blood supply of an ischemic focus and on the plasma enzyme activity in dogs with acute coronary occlusion]. / Vliianie dofamina na pokazateli sistemnoi gemodinamiki, krovosnabzhenie ochaga ishemii i aktivnost' fermentov plazmy u sobak s ostroi koronarookkliuziei.

In acute experiments on anesthetized dogs dopamine (10 micrograms/kg and 10 micrograms/kg/min) was shown to increase significantly the blood supply to ischemic regions and the minute heart volume at the background of insignificant systemic hypotension and tachycardia. When administered in a dose of 10 micrograms/kg/min dopamine increased the magnitude of the ratio of glycogen-phosphorylase b activity to total glycogen-phosphorylase activity in the blood plasma. Administration of 20 micrograms/kg of the drug did not produce a significant increase of the blood supply to ischemic regions and the minute heart volume in the presence of the tendency toward systemic hypotension and bradycardia.

[The specific binding of dihydroalprenolol and quinuclidinyl benzilate with myocardial lysosomes]. / Spetsificheskoe sviazyvanie digidroalprenolola i khinuklidinila benzilata s lizosomami miokarda.

The binding of 3H-dihydroalprenolol and 3H-quinuclidinyl benzylate to lysosomes of the rat ventricular myocardium vas studied. More than one type of specific binding sites of dihydroalprenolol and quinuclidinyl benzylate at the rat myocardium lysosomes were found. The association constants values differ from the known values of the association constants of the same ligands with plasmatic membranes of the mammalian myocardium.

[Action of beta-adrenomimetics on the degree of lysosomal membrane damage and glycogen phosphorylase activity of the ventricular myocardium of guinea pigs]. / O deistvii beta-adrenomimetikov na stepen' povrezhdeniia lizosomal'nykh membran i glikogenfosforilaznuiu aktivnost' v miokarde zheludochkov morskikh svinok.

The effects of partusisten, novodrin and nonachlazine on the acid phosphatase and glycogenphosphorylase activities in the guinea pig ventricle myocardium were studied. The injection of partusisten (1 mg/kg) significantly increased the acid phosphatase activity and preserved the strong negative correlation between the free activity of acid phosphatase seen in control animals and the "free activity/total activity" ratio. Beta adrenergic agonists exerted different effects on the "glycogenphosphorylase B activity/glycogenphosphorylase A + B activity" ratio.

[Action of nonachlazine on the creatine phosphokinase and acid phosphatase activity and on the lysosomal membrane stability of the ischemic myocardium in rats after preliminary reserpinization]. / Deistvie nonakhlazina na aktivnost' kreatinfosfokinazy, kisloi fosfatazy i stabil'nost' lizosomnykh membran ishemizirovannogo miokarda krys posle predvaritel'noi rezerpinizatsii.

Experiments on the ischemic myocardial tissue of the rat in vitro showed that despite the fact that reserpine-induced depletion of the tissue catecholamine storage failed to affect the stability of lysosomal membranes, a combination of reserpine pretreatment of the animals with subsequent administration of nonachlazine at the low dose yielded stabilization of lysosomal membranes to a greater extent than administration of nonachlazine alone. The effects of nonachlazine (0.25 mg/kg) on the activity of creatine phosphokinase and total activity of acid phosphatase with and without reserpine pretreatment were similar.

[Effect of nonachlazine on the temperature sensitivity of the lysosomal membranes of the heart muscle in rats in vitro]. / Vliianie nonakhlazina na temperaturnuiu chuvstvitel'nosti lizosomal'nykh membran serdechnoi myshtsy krys in vitro.

It has been shown in vitro that nonachlazine stabilizes rat myocardial lysosomal membranes and activates total acid phosphatase in homogenates of rat myocardium. Preliminary addition of nonachlazine to homogenates in two different final concentrations produces unequal changes in total and free activity of acid phosphatase and cathepsin D during 2.5-hour incubation of homogenates at 37 degrees C.

[Role of glycogenolysis inhibition in the etiology of arrhythmias in coronary disease]. / Rol'ugneteniia glikogenoliza v proiskhozhdenii aritmii koronarogenno porazhennogo serdtsa.

Under conditions of acute ischemia spontaneous fibrillation which developed in heart ventricles as well as arrhythmias which were medicamentally provoked both were accompanied by a decrease in activity of glycogen phosphorylase a. At the same time, there was a distinct increase of non-phosphorylated isoenzyme ratio to the total phosphorylase activity of the tissue and the total glycogen pool was decreased. The decrease in activity of glycogen phosphorylase a, after pharmacological correction of metabolism of highly ischemized myocardium using obzidan and digoxin at therapeutic doses, occurred simultaneously with a decrease in the level of phosphorylase b activity in the tissue. A hypothesis, considering an increase in glycogenolysis as a trigger mechanism in development of ventricle fibrillation under conditions of acute coronary occlusion, is criticized.

[Effect of prolonged beta-adrenergic blockade on myocardial energy metabolism in coronary occlusion]. / Vliianie dlitel'noi beta-adrenoblokady na énergeticheskii metabolizm miokarda pri koronarookkliuzii.

It has been shown that a single intravenous injection of obsidan (0.1 mg/kg) to dogs during acute coronary occlusion results in a decrease in the activities of "a" phosphorylase, Mg-dependent ATPase, creatine phosphokinase, succinate dehydrogenase and cytochrome-c-oxidase, in a slight lowering of the ATP content accompanied by the increased content of AMP and unchanged concentration of creatine phosphate. Repeated injections of the drug in the same dose raise the activities of the enzymes up to the control level and produce activation of glycogenolysis and succinate dehydrogenase during the reparative period. The drug favours the preservation of "b" phosphorylase activity in the infarcted tissue and does not change the content of adenine nucleotides and creatine phosphate upon prolonged application.