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Biomedical subjects

A A Lebedev

Publications and source records attributed to A A Lebedev.

151 records · Page 9Linked to original sources
PubMedDate not supplied

[Lysergic acid diethylamide blockade of the brain serotoninergic receptors prevents the facilitating effect of phenamine on self-stimulation in rats with destruction of the medial prefrontal cortex].

Amphetamine (1 mg/kg) increased the rate of pedal self-stimulation of the lateral hypothalamus of Wistar rats in Skinner box by 37%. Lesion of the medial prefrontal cortex with kainic acid (16 mcg/kg in 8 mcl) 10-14 days prior to the experiment did not prevent facilitating effect of amphetamine on self-stimulation. Lysergic acid diethylamid (10 mcg/kg) did not influence self-stimulation response in rats with damaged medial prefrontal cortex, but after its preliminary administration prevented the stimulating effect of amphetamine on self-stimulation of the lateral hypothalamus. The findings are discussed from two points of view: 1) the phenomenon observed is associated with the existence of hypothalamic autoregulatory dopaminergic system which provides realization of self-stimulation; 2) modulating influence of the medial prefrontal cortex on the lateral hypothalamus is mediated not only by dopaminergic but also by serotoninergic axons. It is suggested that both mechanisms may underlie the phenomenon under study.

Amphetamine↗
PubMedDate not supplied

[The binding of furosemide and ethacrynic acid with different types of biological membranes].

The study was undertaken to examine the effects of furosemide and ethacrynic acid on the fluorescence of 1,8-AHC in the suspension of erythrocytic membranes and lumenal and basolateral membranes of the rat renal epithelium. Ethacrynic acid was demonstrated to decrease probe luminescence in all three types of biological membranes. Furosemide failed to affect 1,8-AHC fluorescence in the suspension of blood ghosts and basolateral membranes of the renal epithelium and enhances probe fluorescence in the suspension of luminal membranes. The constants of binding of diuretics to the biological membranes were calculated. The effects of diuretics on the tryptophan fluorescence of renal epithelial luminal and basolateral membranes were studied in one of the series of experiments. It is suggested that the conformational rearrangements in the renal epithelial basolateral and luminal membranes can occur with ethacrynic acid. Furosemide in a dose of 10(-3) M showed the same effect only against luminal membranes.

Anilino Naphthalenesulfonates↗
PubMedDate not supplied

[The antioxidative properties of furosemide in renal ischemia].

The intensity of lipid peroxidation increases in ischemic damage to the kidneys. That furosemide possesses antioxidant properties was established on a model of in vitro total kidney ischemia. It is supposed that the protective effect of furosemide in ischemic damage is due to inhibition of lipid peroxidation. However, such an effect is not encountered in kidney ischemia in an intact organism. Furosemide does not prevent the fall of selenium concentration in the kidney after ischemia.

Animals↗
PubMedDate not supplied

[The phenomenon of resistance to a thiazide diuretic in acute kidney failure].

The resistance to hypothiazid (hydrochlorothiazide) during the development of acute renal insufficiency (ARI) induced by glycerin injection was studied in rat experiments. Natriuretic, kaliuretic, and hydrouretic activity of the diuretic decreased two days after injection of a glycerin solution. In this period hypothiazid excretion with the urine was least. Ten days later, despite the restoration of the water- and electrolyte-excretion function of the kidneys and normalization of hypothiazid excretion with the urine, the natriuretic effect of the drug was still very poor. This is indirect evidence of the long-term affection of the receptors for the thiazid diuretics during the development of ARI. The affection remains even after the excretory function of the kidneys is restored. The high correlation between the cumulative excretion of hypothiazid with the urine and natriuresis encountered in intact animals was weaker in rats with acute renal insufficiency.

Acute Kidney Injury↗
PubMedDate not supplied

[A comparison of the effects of dopamine agonists on self-stimulation of the hypothalamus with destruction of the mesolimbic brain structures in rats raised under conditions of social isolation].

In rats bred in groups or under conditions of social isolation, amphetamine administration did not change significantly the basic rate of hypothalamic self-stimulation. The unilateral lesions of ventral tegmental area and medial prefrontal cortex in the early ontogeny (on the 17th day after birth) increased the sensitivity to amphetamine only in isolated rats. Apomorphine, the dopamine receptor agonist, in the dose which mainly affected the presynaptic receptors (0.05 mg/kg) inhibited self-stimulation by 21-23% both in grouped and socially isolated rats. Destruction of the ventral tegmental area did not change, but that of the medial prefrontal cortex doubled the sensitivity of isolated rats to apomorphine. It is suggested that the hypersensitivity of presynaptic dopamine receptors in the mesocorticolimbic system develops as a result of partial sensory and full intraspecies isolation in rats.

Amphetamine↗
PubMedDate not supplied

[The attitude of health personnel and population toward the economic reform in public health system. (The results of a survey in Chelyabinsk)].

Sociologic survey of the knowledge of the population and medical workers about the new economical relations in public health system, including medical insurance, showed that both the population and medics understand the necessity of public health reformation, introduction of new economic relations, and medical insurance. The major part of the population is ready to pay for medical service, but cannot afford it.

Adult↗