[Role of SH-groups in the pharmacology of the action of novurite and ethacrynic acid]. / Rol' SH-grupp v realizatsii éffektov novurita i ítakrinovoi kisloty.

In experiments in vivo the mercuric diuretic, novurite, and ethacrynic acid in therapeutic doses (25 and 50 mg/kg, respectively) do not block the respiration and active transport of calcium in the kidney mitochondria. The diuretic effect of these substances is not prevented by cystein (50 mg/kg), the donator of sulphydryl groups. In vitro novurite (3 mM) and ethacrynic acid (1 mM) block the systems of ionic transport inthe kidney epithelium cells and in concentrations of 0.2 and 0.5 mM, respectively, disturb the oxygen uptake and oxidative phosphorylation in the kidney mitochondria. A preliminary administration of cystein (5 mM) into the incubation medium prevents these effects. Novurite and ethacrynic acid manifest the typical thyol toxins of general cell effect in doses considerably exceeding the therapeutic ones. A specific "kidneys" effect of these substances is not connected with their ability to block SH-group of biologically active substances.

[Effect of gentamycin on the kidney functional state in experimental pyelonephritis]. / Vliianie gentamitsina na funktsional'noe sostoianie pochek pri éksperimental'nom pielonefrite.

The experiments with rats treated with gentamicin showed that nitrogen excretion function of the kidneys did not significantly change in the animals 3 months after induction of pyelonephritis, while in the animals not treated with the antibiotic there was a significant increase in excretion of alkaline phosphatase with urine. The nitrogen excretion function of the kidneys was not affected by gentamicin, except an increase in the urea blood level. Gentamicin promoted a significant rise in excretion of enzymes with urine, especially that of alkaline phosphatase. Treatment of healthy animals with gentamicin resulted in the increased excretion of alkaline phosphatase with urine and increased urea blood levels which was evident of the nephrotoxic effect of the aminoglycoside antibiotic. When such animals were treated with furosemide, the renal excretion of the enzyme and the blood creatinine urea levels decreased. Therefore, furosemide lowered nephropathy induced by gentamicin. The increase in the activity of the urine enzymes may be due to inflammatory changes in the kidney parenchymal on the one hand and the pephrotoxic effect of the drugs on the other hand. The urine enzymes may be used as important diagnostic tests in cases with kidney affections and indicators of safe treatment with nephrotoxic antibiotics.

[Use of gentamycin and furosemide in acute pyelonephritis (an experimental morphological study)]. / Primenenie gentamitsina i furosemida pro ostroi pielonefrite (éksperimental'no-morfologicheskoe issledovanie).

The favourable effect of gentamicin and its combination with furosemid was shown in treatment of rats with experimental pyelonephritis. However, alongside the favourable effect, a danger of the gentamicin nephrotoxic effect, especially in combination with furosemid was noted. The nephrotoxic effect was evident from foci of distrophic and necrobiotic changes in the epithelium of the convoluted tubules, impairment of the cortical hemodynamics and development of the cortical hypoxia of the kidneys resulting in severe renal insufficiency. Gentamicin had no direct inhibitory effect on the tissue respiration, did not block the oxygen uptake and oxidative phosphorilation in isolated mitochondria. To prevent the development of the nephrotoxic effect of gentamicin and its combination with furosemid strict and effective control of the antibiotic plasma levels is necessary. Informative tests for the control of the renal function are the concentration parameters of creatinine and urea, especially at the beginning of the pathological state when the level of hyperazotemia is still of a low informative value. The diurnal urine excretion is not an important informative index of renal function.

[Mechanism of the therapeutic effect of furosemide and mannitol in hemorrhagic shock and developing acute renal insufficiency]. / Mekhanizm lechebnogo éffekta furosemida i mannitola pri gemorragicheskom shoke i razvivaiushcheisia ostroi pochechnoi nedostatochnosti.

Acute hypotension leads to the development of anuria, almost complete stoppage of the cortical nephron filtration with blood retransfusion failing to restore the upset functions. But against background of preliminary administered diuretics the blood retransfusion renews filtration and restores diuresis. Preliminary administration of diuretics prevents collapse of the proximal tubules, their administration after blood losses increases the tubular pressure and prevents obstruction of the nephron. Under the effect of diuretics the oxygenation of deep-seated segments of the kidney substantially gains in strength due to an increasing renal blood circulation and diminished vasoconstriction. Diuretics increase the oxidative phosphorylation in the cells of the renal epithelium, help augment accumulation of calcium by renal mitochondria and prevent the development of irreversible hypoxic shifts. Combined administration of furosemide and mannitol represents an effective means of prevention and early treatment of acute renal insufficiency.

[Role of the dopaminergic structures of the kidney in the renal effects of euphyllin]. / Rol' dofaminergicheskikh struktur pochki v renal'nykh éffektakh éufillina.

Reserpine and galoperidol are shown to exercise blocking effect with regard to the diuretic and saluretic action of the xanthine-euphylline. Galoperiod prevented an accretion of the total renal blood flow induced by euphylline. Preliminary introduction to rats of alpha-methyl-DOPA and 1-DOPA abolished the blocking action of reserpine on the renal effects of euphylline. The renal influence of euphylline is mediated through dopamine-ergic structures, which are non-identical to adrenostructures. Dopamine is not merely a precursor of norepinephrine and epinephrine, but performs functions of its own in the organism.

[Effect of catecholamines on sodium resorption and oxygen tension in rat kidneys]. / Vliianie katekholaminov na reabsorbtsiiu natriia i napriazhenie kisloroda v pochke prys

Functional significance of alpha- and beta-adrenoreceptors for the mechanism of catecholamines effect on sodium reabsorption and oxygen tension in the rat kidney, was studied. Adrenaline inhibited sodium excretion decreasing its filtration in glomeruli and stimulating its reabsorption in tubules. The oxygen tension in these conditions did not change in the renal cortex while oxygenation of the external cortical layer was significantly increased. The blocking agent for alpha-adrenoreceptors phentolamin abolished the inhibiting effect of adrenaline on the glomerular filtration and somewhat decreased the degree of oxygen tension growth in the external cortical layer, leaving the tubular effect unaltered. The blocking agent for beta-adrenoreceptors inderal did not affect the inhibitory action of adrenaline on the glomerular filtration but completely prevented its activating effect on the tubular reabsorption of sodium and on oxygenation of the external cortical layer. A conclusion was drawn that catecholamines stimulation of sodium reabsorption in the rat kidney follows excitation of beta-adrenoreceptors. The increase in oxygen tension in the external cortical layer under effect of catecholamines is supposed to improve energetic supply of the sodium active transport in the ascending portion of the Henle loops.

[The hydrodynamics of the superficial cortical nephrons of the rat kidney during a diuretic response]. / Gidrodinamika poverkhnostnykh kortikal'nykh nefronov pochki krys vo vremia diureticheskoi reaktsii

Diuretic response to administration of mannitol, furozemide, ethaerynic acid, and euphyllinum was invariably followed by a considerable dilation of the lumen of proximal and distal tubular of the kidney surface nephrones. Simultaneously, a considerably reduced flow of the tubular fluid was always observed except after euphyllinum administration, the latter being followed by acceleration of the flow. Questions of interrelationships between the nephrone's hydrodynamic characteristics and the processes of glomerule filtration and tubular reabsorption of the fluid and electrolytes, are discussed.

[Mechanism of the diuretic effect of eufillin]. / O mekhanizme diureticheskogo éffekta éufillina

In acute experiments on rats the xanthine diuretic euphylline did not block the short-circuited current in the proximal tubule, nor did it lower the transtubular potential and the transepithelial resistance of the nephron wall. The diuretic speeded up significantly the passage of the tubular fluid along the proximal region of the nephron and Henle's loop. The dihydroergotoxin and inderal blocking of adrenoreceptors did not produce any influence on the renal effects of the xanthine agent. Reserpine totally blocked the diuretic and saluretic effects of euphylline, whereas other sympatholytics, such as alpha-methyl-dofa, anthabus and hemedin, did not modify the action of the diuretic.

[Diuretics as factors regulating electrolyte transport through the wall of the kidney tubule]. / Diuretiki kak faktory, reguliruiushchie perenos elektrolitov cherez stenku pochechnogo kanal'tsa

The effects of furosemide, hydrochlorthiazide, triamteren and mannitol on the intratubular potential, electric resistance of the wall of the proximal and distal renal tubule and also changes in the magnitude of the short-circuited current that give an idea as to the tubular transport of sodium in the proximal section of nephron were explored electrophysiologically on a renal nephron of the rat. Furosemide and hydrochlorthiazide depressed the magnitude of the short-circuited current in the proximal end of nephron and raised the transtubular potential. Hydrochlorthiazide also tended to increase the electric resistance of the renal tubule wall. Triamteren forced down the potential in the proximal end of nephron, as well as the magnitude of the short-circuited current, but did not change the tubular wall resistance. Mannitol drastically reduced the tubular wall resistance and the intratubular potential, without affecting the short-circuited current. A classification of diuretics by the mode of their action on the electric parameters of the nephron is given.