PubMed Health⌕ Search

Biomedical subjects

A M Mendzheritskiĭ

Publications and source records attributed to A M Mendzheritskiĭ.

At least 19 recordsLinked to original sources
PubMed2005

[Adrenocortical and thyroid systems of rats at the initial stage of nociceptive influence].

There are two phases in the initial period of formation of adrenocortical response to sharp nociceptive influence. The first phase (within 10-15 sec.) involves emergency mobilization of "basal" reserves of hormone active substances. It is characterized by reduction of corticoliberine activity in hypothalamic and extrahypothalamic structures of the rat brain with a parallel increase of corticotrophin concentration in plasma, devastation of corticosteroid reserves in adrenal glands; a decrease in the level of corticosteroids in blood against the background of accumulating hormone in bodies-targets. In the second phace: the phase of hypercompensation, the progressive increase of credit of the substances under study was quite obvious. The authentic changes in a level of aldosterone in adrenal glands and blood took place only in 2.5 minutes after the stress. The nociceptive influence was also biphasic when acting upon the reorganization of thyroid status number. However, unlike the initial adrenocortical response to stress in the first phase of thyroid reaction, the elevation of plasma thyroxine and tri-iodothyronine level was obvious. At the second stage, selective decrease in concentration of thyroxine to normal amounts occurred.

Adrenal Cortex Hormones↗
PubMed1996

[The mechanism of the anticonvulsive effect of the delta sleep-inducing peptide under conditions of elevated oxygen pressure].

Delta-sleep-inducing peptide (DSIP) exerted a protective effect against seizures, the effect depending on the DSIP ability to create an optimal ratio between inhibitory and excitatory amino acid neurotransmitters. Administration of the DSIP dramatically increased the contents of gamma-aminobutyric acid and homocarnosine while decreasing the glutamate and aspartate contents in the rat brain cortex.

Animals↗
PubMed1995

[Proteolytic processes in the rat brain and serum in hypokinesia and the adaptive effect of delta-sleep inducing peptide].

It has been demonstrated for the first time that a single injection of the delta-sleep inducing peptide (DSIP) results in long-term alteration of proteolytic enzyme activity within a broad range of pH. Using Ca(2+)-independent neutral endopeptidases from the synaptosomal fraction of rat brain and blood serum kallikrein as an example, it has been shown that DSIP activates limited proteolysis. This effect may contribute to the alteration of the set and "active" concentration of regulatory peptides and peptide hormones to the induction of the preadaptive state. DSIP also causes the redistribution of activity between Ca(2+)-dependent and Ca(2+)-independent neutral endopeptidases associated with synaptosomal membranes, particularly under hypokinetic conditions. The significant decrease of the Ca(2+)-activated neutral proteinase I activity may be one of the mechanisms whereby the modulating effect of DSIP manifested as regulation of the number of glutamate receptors and limitation of effect of this excitatory neuromediator is realized under stress. Preliminary injection of DSIP prevents disturbances in the permeability of lysosomal membranes under long-term (24 hours) hypokinesia.

Adaptation, Physiological↗
PubMed1992

[The electrophysiological and ultrastructural aspects of the effect of increased oxygen pressure on the sensorimotor cortex of rats].

Stay of the rats in barochamber under 0.3 MPa oxygen during 2 hrs induced separate sharp waves with no generalisation, the electron microscopic changes expressing activation of compensatory-adaptive processes. The generalisation of seizure activity over the cortex at 0.7 MPa oxygen affects a part of neuronal pool due, probably, to irreversible changes in inhibitory axosomatic synapses.

Animals↗
PubMed1992

[Morphometric evidence of activation of axo-somatic synapses during administration of delta sleep-inducing peptide].

Computed morphometry proved activation of neocortex layer III-V axosomatic synapses. This is evident from an increase in the mean plasmalemma length, that in the active synapse zones on neurone bodies and width of the synaptic cleft, this being induced by a single intraperitoneal administration of delta-sleep-inducing peptide. The activation of the axosomatic synapses correlates with elevated GABA levels in the cerebral hemispheres cortex.

Animals↗
PubMed1982

[Hypnogenic effect of antibodies to myelin basic protein administered intraventricularly].

Intraventricular administration of myelin basic protein amtibodies in rabbits evoked high-amplitude slow waves in the ECoG, the animal takes a characteristic sleep posture, muscular tension weakens, the nictitating membrane lowers down, and the respiratory rhythm becomes stable. Spontaneous activity and arousal as well as recruiting responses induced by electrical stimulation of the thalamic CM in the cortical and thalamic structures suggest that the state resulting from the anti-BP antibodies administration is similar to slow wave sleep. The effect of anti-BP antibodies administration seems to be due to direct influence upon synaptic events in the thalamic "sleep-inducing" structures.

Animals↗
PubMed1982

[Dicarboxylic amino acids in brain proteins under conditions of sensitization with brain antigen].

Under conditions of the organism sensibilization with brain antigen there occur changes in amino acid composition of the brain protein fractions. The ratio of negatively charged amino acids to positively charged ones in sharply shifted towards predominance of the negative charge. A conclusion is made that such a brain protein modification activates acid peptide hydrolases and intensifies the sensibility of the proteins to these acid proteinases.

Amino Acids, Dicarboxylic↗
PubMed1979

[Characteristics of myelin basic protein from dog spinal cord].

Some characteristics of the myelin basic protein from dog spinal cord were studied. The basic protein has a molecular weight of 18,000; the isoelectric point is 9.5. The amino acid composition of the protein was determined. Electrophoresis in 15% polyacrylamide gel revealed the heterogeneity of the basic protein. The EAE-activity of the basic protein was tested on guinea pigs.

Amino Acids↗
PubMed1978

[Nonenzymatic deamidation as a factor in protein aging].

Amidation of two protein fractions of brain, heart and liver of senite rats was found to decrease by 15--21% as compared with that of young animals. This decrease was shown to be due to unstable amide groups. Strong evidence is presented favouring the preposition that in proteins the unstable amide groups are those of asparagine and the stable ones those of glutamine. The possibility of the nonenzymatic deamidation of proteins was investigated. Deaminated proteins were found to be more easily attacked by proteinases which could be one of the possible ways of breakdown of aging proteins.

Aging↗
PubMedDate not supplied

[Pentylenetetrazole kindling induces caspase-3 activation in rat brain].

Pentylenetetrazole kindling (but not a single pentylenetetrazole injection) induced caspase-3 activation in the cerebral cortex, hippocampus, and cerebellum of rats as well as neurodegeneration in the hippocampus. The number of neurons in the CA3 subfield of the hippocampus decreased significantly, whereas no apoptotic nuclei could be detected. The results support a possible non-apoptotic involvement of caspase-3 in brain plasticity.

Animals↗
PubMedDate not supplied

[Influence of delta-sleep-inducing peptide on the activity of proteolytic enzymes in the rat brain under hypokinesia].

Single administration of the delta-sleep-inducing peptide (DSIP) in a dose of 12 micrograms/100 g to intact animals makes the activity of neutral proteinases and cathepsin D higher in the rat brain and blood serum. Hypokinesia of different duration changes activity of neutral and acidic proteinases and induces accessibility of cathepsin D to the cytosol as a result of damage in lysosomal membrane. Injection DSIP induces a decrease A/B of cathepsin D to the control level under 1-h hypokinesia condition and normalizes the neutral proteolytic activity under 6-h hypokinesia condition.

Animals↗
PubMedDate not supplied

[Antistressor effect of delta-sleep-inducing peptide in hypokinetic stress].

The influence of DSIP injection on the levels of neurotransmitters during hypokinetic stress was studied. It was shown that hypokinesia produced considerable changes in the levels of GABA glutamate, aspartate and homocarnosine. The injection of DSIP normalized the level of neurotransmitter amino acids. Administration of DSIP also reduced stress-induced changes in the activity of enzymes of GABA metabolism. Stress protective effect of DSIP was also demonstrated by normalising of the POL of lipids in brain.

Animals↗