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Saint Petersburg, Russia

Zolotarev V.A.,RAS Pavlov Institute of Physiology
Current Pharmaceutical Design | Year: 2014

In the stomach, pre-absorptive perception of food constituents is of particular importance in maintaining secretion and motility that matches the quantity and quality of nutrients. Products of food protein hydrolysis, free amino acids and short peptides, are the most potent chemical stimulants of the gastric phase of digestion. They are recognized by a variety of extracellular receptors belonging to the G-protein-coupled receptor superfamily, which are expressed by gastric mucosal exocrine and endocrine cells. Enteroendocrine G and D cells are likely the first level of integration of amino-acid-induced signals influencing a balance of endocrine activation and inhibition of gastric functions. This review focuses mainly on the physiological significance of dietary L-glutamate (Glu) in control of the gastric phase of digestion. The Glu signaling system in the stomach is linked to activation of the vagal afferents. In contrast to other natural amino acids, luminal Glu activates a paracrine cascade led by nitric oxide and followed by serotonin (5-HT), interacting in turn with 5- HT3 receptors on the afferent endings in the sub-mucosal layer. Glu, the only amino acid regularly ingested in a free form, enhances secretory and gastroprokinetic responses to protein- and amino-acid-rich diets but has no effect when applied alone or with carbohydrates. Possible mechanisms are discussed. © 2014 Bentham Science Publishers.

The present study provides evidence for anti-ictogenic activity of the mystixin 7 (MTX) mini-peptide in the pentylenetetrazole model of seizure. MTX was effective in inhibiting/suppressing ictal- and interictal-like activities over a long period of time (during 60-80. min). The peptide's anti-ictogenic effects were concentration- and time-dependent. An enzymatic treatment of MTX was accompanied by a decrease of the frequency pattern of epileptiform discharges, but their total blockade did not occurred. These findings indicate that the MTX mini-peptide has pronounced anti-ictogenic properties. © 2014 Elsevier B.V.

Ivanov K.P.,RAS Pavlov Institute of Physiology
Respiratory Physiology and Neurobiology | Year: 2013

Human lungs weighing ca 600. g permit the passage of 5-6. l of blood per minute. The blood capacity of the human lungs is about 0.5. l. Consequently, each 0.5. l of blood is during 5. s. The questions arise of how such a large mass of blood passes through such a small mass of lungs and what the reasons are for such a high rate of blood oxygenation. Since the structure of lungs in mammals is almost the same, we tried to solve these issues studying the rats, in which 20-22. ml of blood pass through the lungs of 1.5-2.0. g mass. A great blood flow appeared to be associated with a large diameter of the lung arterioles and a high rate of the blood flow in them. The high rate of oxygenation is accounted for by a special structure of alveoli and special conditions of the blood flow, which create ideal conditions for oxygen diffusion. © 2013 Elsevier B.V.

Galeeva A.,RAS Pavlov Institute of Physiology
Vitamins and hormones | Year: 2010

Corticosteroid hormones are important intrinsic factors that not only mediate the response to stress but also largely contribute to the main physiological processes. The biological actions of these steroids involve, first of all, the activation of specific receptors, namely mineralocorticoid (MR) and glucocorticoid (GR) receptors. These two receptor types govern a flexible and well-balanced mechanism that leads to the often opposing changes in the cell. The hippocampus is the central part of the extrahypothalamic feedback loop in the control of the hypothalamic-pituitary-adrenal (HPA) axis activity. The coexpression of both MR and GR in the hippocampus serves a coordinated response to corticosteroids in the hippocampal neurons, thereby mediating the neuronal excitability, stress response, and behavioral adaptation. Each receptor type reveals distinct ontogenetic pattern over the postnatal period. This review addresses the issues relating to postnatal development of the HPA axis and especially the hippocampal expression of the GR proteins in intact and prenatally stressed rats. Copyright 2010 Elsevier Inc. All rights reserved.

Danilova M.V.,RAS Pavlov Institute of Physiology
Journal of vision | Year: 2010

Are boundaries between color categories associated with enhanced discrimination? In the present experiments, chromatic thresholds were obtained for discriminations along lines orthogonal to the yellow-blue axis of color space. The targets were parafoveal and thresholds were measured with a spatial two-alternative forced choice. In interleaved experimental runs, we also obtained empirical estimates of the subjective yellow-blue line by asking observers to categorize colors as reddish or greenish. Both types of measurement were made in the presence of a steady background that was metameric to equal-energy white. In a limited region from desaturated yellow to desaturated blue, an enhanced discrimination is found near the subjective transition between reddish and greenish hues. This line of optimal discrimination is not aligned with either of the cardinal axes of color space: In a MacLeod-Boynton chromaticity diagram, it runs obliquely with negative slope.

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