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Biomedical subjects

N A Emel'ianov

Publications and source records attributed to N A Emel'ianov.

At least 19 recordsLinked to original sources
PubMed2003

[Effect of corticotropin-releasing factor on anoxia-induced changes in evoked potentials in cultured tissue of the rat olfactory cortex].

The experiments were performed on incubated slices of the rat rostal olfactory cortex. The slices were treated with various concentrations (10(-7) to 10(-9)) of corticotropin-releasing factor before (40 min), during, and after a 10-minute anoxic episode. The parallel control experiments were carried out without CRF. A 10-minute anoxia, both in control experiments and in perfusion with CRF, resulted in an approximately equal decrease of field excitatory postsynaptic potential's (fEPSP) amplitude. However, CRF at 10 nM and 100 nM concentrations protected the fEPSP amplitude. The selected NMDA receptor antagonists 2-amino-5-phosphonopentanoate (AP5) added in the perfusion medium after the anoxia, did not eliminate the neuroprotective effect of CRF.

Animals↗
PubMed1997

[45Ca metabolism in slices of rat cerebral cortex during long-term potentiation].

Ca45 kinetics was studied in 5, 15 and 30 min after potentiation. In the induction phase (1-5 min), the potentiation decreased the fraction of intracellular bound Ca. The 15-25 min potentiation the intra- and extracellular Ca levels was equal to the control ones. In 30 min, a considerable redistribution of Ca in the cells occurred.

Animals↗
PubMed1995

[Correlates of membrane metabolism and long-term potentiation in slices of rat cerebral cortex].

A group of interrelated parameters of the membrane metabolism was studied during stimulation of the lateral olfactory tract in the rat brain slices of olfactory cortex. All the parameters were studied in respect to electrical activity of the slices in three temporal points after the tetanisation: 3-5, 15, and 30 min. Regular phasic alterations of the metabolism parameters occurred in most of the cases. Their functional significance is discussed.

Animals↗
PubMed1992

[The functional plasticity of the cells of the paraventricular nucleus in surviving slices of the hypothalamus].

In surviving cuts of the hypothalamus, stimulation of the supraoptic nucleus induced focal potentials in the paraventricular nucleus. A repeated stimulation was followed by a reduction of the descending of the focal potentials. Tetanization of the supraoptic nucleus induced an additional wave at the descending phase of focal potentials preserving for 15 min. The data obtained suggest a functional plasticity of the hypothalamus paraventricular nucleus' cells.

Action Potentials↗
PubMed1991

[The effect of the tripeptide melanostatin on phospholipid metabolism in the olfactory cortex of rats].

The incubation of the brain slices with melanostatine for 15 min increased the contents and reduced the metabolism intensity of phosphatidylcholine and phosphatidyletanolamine in the rat olfactory cortex. The sphingomyelin metabolism intensity was increased. These shifts in the metabolism of membraneous components may cause considerable modifications in the membranes properties and can be a material basis for long-term changes in the unit activity.

Acetates↗
PubMed1990

[The effect of hydrocortisone on posttetanic potentiation in rat cerebral cortex slices and the molecular mechanisms of this effect].

The effect of hydrocortisone on posttetanic potentiation, Ca exchange, metabolism of phosphoinositides and phospholipids methylation, was studied. Hydrocortisone (10(-4) M) facilitated and prolonged the posttetanic potentiation. Incubation of slices in hydrocortisone for 90 sec elevated the incorporation of 32P-orthophosphate in polyphosphoinositide. Within 2 min of hydrocortisone action, the rate constant of Ca entry increased two-fold, transmembrane exchange fluxes of Ca increasing, too. Incorporation of 14C-methyl group in different phospholipids was considerably increased after 20-min hydrocortisone action.

Animals↗
PubMed1990

[The neurotropic effects of hydrocortisone in surviving slices of the rat olfactory cortex].

The effects of hydrocortisone on short-term habituation, post-tetanic potentiation, fluctuations of the amplitude of focal potentials (FPs) and slow after-hyperpolarization were studied in the olfactory cortex slice preparations. Hydrocortisone (10(-5)-10(-4) M) inhibited the habituation but facilitated and prolonged the post-tetanic potentiation of the FPs. The hormone increased the fluctuations of the FPs and exerted no effect on slow after-hyperpolarization evoked by a brief orthodromic stimulation. The neurotrophic effects of the hydrocortisone seem to reflect adaptive reactions of nervous system under stress conditions.

Animals↗
PubMed1990

[Posttetanic and frequency potentiation in slices of the olfactory cortex from the rat brain].

A 15-sec tetanization of lateral olfactory tract at the frequency of 30/sec produced a short-term (20 min) posttetanic potentiation of the field potentials (FPs) in the rat olfactory cortex slices. Rhythmical stimulation of lateral olfactory tract (6 trains of 10 pulses each at the frequency of 10/sec, with 4-5 sec intertrain interval) evoked a progressive increase in the amplitude of postsynaptic components of the FPs (EPSP and IPSP) but not in amplitude of presynaptic component--the compound AP of lateral olfactory tract. The findings suggest the development of the 2-form functional plasticity: posttetanic and frequency potentiation in pyriform cortex.

Animals↗
PubMed1988

[Effect of the tripeptide melanostatin on the electrical activity of surviving slices of the olfactory cortex in the rat brain].

The effects of melanostatin (MST 10(-5) M) on transmission in the lateral olfactory tract--superficial pyramidal neurons synapses, were investigated in slices of the rat olfactory cortex. Within 3-6 min after MST addition, the EPSP amplitudes were depressed and then increased (within 6-9 to 30 min); spikes and IPSPs appeared during the latter period. The recovery of the FPs to control values at washing was slow (40-60 min). Possible mechanisms of the MST long-term excitatory effect on neural elements of the slices, are discussed.

Animals↗
PubMed1983

[Metabolism of 22Na in the rat corpus callosum].

The kinetic parameters of 22Na+ exchange were measured with improved compartmental analysis in slices of rat corpus callosum. Three distinct Na compartments were found: 45, 38 and 15% of the total Na+, having T1/2 for efflux 7.3; 43.5 and 119 s, resp. Transmembrane Na flux was 2.4 M/g/hr. The obtained kinetic parameters were compared to those in neocortex and hippocampus.

Animals↗
PubMed1981

[Effect of multiple administrations of hydrocortisone on the functional activity and morphological characteristics of motor neurons].

Effects of repeated (for 5 days) injections of hydrocortisone (HC) per 1 mg dialy was studied using frogs Rana temporaria. The functional and morphological parameters of spinal motoneurones were investigated. The repeated administrations of HC diminished the excitability of spinal elements, prolonged the latency, and decreased the amplitude of ventral root potentials in response to single stimula applied to dorsal roots. Simultaneously, some structural changes occurred in motoneurones examined: swelling of the cytoplasm and the nucleus, chromatolysis of cell processes, nucleolar hypertrophy, increase in glycogen granule density, swelling of synapses. A suggestion is made that the repeated hormone administration caused in nervous cells some destructive changes of exhaustive type.

Animals↗