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Biomedical subjects

G S Voronkov

Publications and source records attributed to G S Voronkov.

At least 37 records · Page 2Linked to original sources
PubMedDate not supplied

[Computer modeling of mechanisms of the information processing in the olfactory bulb. I. Model of the structure-functional organizations of neuronal elements in the olfactory bulb and receptor epithelium].

A computer model of the olfactory bulb was constructed. The paper describes: 1) the general architecture of a model neuron network that reflects the neurophysiological experimental and theoretical data on the structural and functional organization of the peripheral part of the olfactory system, the olfactory bulb with inputs from olfactory receptor neurons; 2) the organization of each of three levels of the model: receptors, olfactory glomeruli, and basic neurons; and 3) a scenario of the computer model work. In some aspects, in particular, in the principle of information presentation, the treatment of the role of basic neurons (mitral and tufted cells), and their interrelations in modules, the model favorably differs from the available olfactory bulb models. The model is basic and provides further refinement of the architecture, an increase in the number of modules, and the modeling of the learning process.

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[Computer modeling of mechanisms of the information processing in the olfactory bulb. II. Mechanisms of identification and short-term storage in the olfactory bulb: results of the computer experimentation].

The results of experimentation with the computer model of the olfactory bulb are presented. The architecture and scenario of the work of the model were described previously. The dynamic character of the identification process and the mechanism of memorizing short-term of smell stimuli are described. During the identification, a self-adjustment of the olfactory bulb to incoming signals occurs. The self-modification of mitral and tufted cell synapses enhances responses of the cells; upon subsequent presentation of the stimulus, the olfactory bulb responds with a higher activity. The modeling confirmed the validity of the assumption that the functions of mitral and tufted cells are to identify the components of a complex smell and the image of the smell as the whole.

Animals↗
PubMedDate not supplied

[Catecholamine concentration and metabolism in old age].

As shown by examination in apparently healthy persons aged from 20 to 100 years and in experiments on 1--28-month-old albino rats there was a significant change with the progress of age in the content and ratio of catecholamines in the blood, various organs and the urine. The blood noradrenaline level fell considerably; Na/A coefficient also dropped sharply. Catecholamine content in the organs changed irregularly: in the kidneys it increased, in the skeletal muscles--remained unchanged, in the adrenal glands, the heart, the spleen and the liver--decreased. There was a significant reduction with the progress of age of the urinary excretion of adrenaline, noradrenaline, DOPA and vanilyl-amygdalic acid. Elemination of the intravenously injected noradrenaline from the blood of old rats was markedly delayed in comparison with that in the young animals. Depression of the COMT activity did not alter the noradrenaline level in the heart of adult and old rats. Administration of ipraside caused an increase in noradrenaline content in the heart of old rats, but failed to alter it in adult animals. It is suggested that in the catecholamine metabolism of old animals prevalence is given to the processes of oxidative desamination.

Adrenal Glands↗
PubMedDate not supplied

[Computer modeling of information processing mechanisms in the olfactory system. III. Reproduction of psychophysical phenomena by the olfactory bulb model].

Psychophysical phenomena typical of olfaction were reproduced using a computer model of olfactory bulb. The procedure of numerical experiments is described. The model reproduces the following phenomena: fusion of odors, strong and weak odors, suppression of weak odors by strong odors, indemnity of odors, changes in odor with time, consecutive olfactory images, sensibilization, consecutive olfactory constrast, and synergims. It was concluded that computer-assisted experimentation in combination with neurophysiological and psychophysical experiments can considerably increase the efficiency of research of odorants and the olfaction process.

Computer Simulation↗
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[The activity of mitochondrial enzymes in the myocardium in chronic coronary failure during the administration of antianginal agents].

The experiments with Chinchilla rabbits indicated that the activity of mitochondria-associated enzymes changed hetero-directionally in chronic coronary insufficiency. The activity of creatine kinase changed most greatly. Obsidan and finoptin were found to show a different effect on the activity of the tested enzymes in the cardiac mitochondria during experimental coronary insufficiency.

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[Creatine kinase in subcellular components of the rabbit myocardium during experimental obstruction of the coronary circulation].

Acute myocardial ischemia (intravenous 0.2 U/kg vasopressin infusion) is shown to cause various changes in the creatine kinase isoenzyme activity: it decreases in mitochondria and sarcoplasmic reticulum and increases in myofibrils and cytosol, no significant alterations taking place in sarcolemma. It may be suggested that the stated changes are important components of the complex adaptational reactions which occur in the ischemic myocardium and support its main contractional function.

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[Relation between the impairment of creatine kinase activity and lipid peroxidation in the membranes of heart mitochondria and sarcoplasmic reticulum in experimental ischemia].

Experiments were conducted on rabbits under conditions of acute restriction of coronary blood flow (intravenous injection of vasopressin in a dose of 0.5 U/kg) and preliminary administration (1 h before vasopressin) of PP-256-Na antioxidant preparation. The activity of creatine kinase isoenzymes bound with sarcoplasmic reticulum and mitochondria membranes were studied as well as the content of diene conjugates in these membranes and accumulation of malonic dialdehyde. It is shown that an essential decrease in the enzyme activity in the membranes occurs against a background of a considerable increase in the content of diene conjugates and accumulation of malonic dialdehyde. A preliminary administration of the antioxidant produces a pronounced protective effect on the enzyme activity.

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[Incorporation of radioactive phosphorus into creatine phosphate of the rabbit myocardium in experimental coronary insufficiency].

It is shown that under conditions of experimental limitation of coronary blood flow in rabbits the intensity of radioactive label (32P) incorporation into creatine phosphate lowers essentially. This evidences for inhibition of creatine phosphorylation in mitochondria under ischemia due to a decrease in the activity of a mitochondrial isoenzyme of creatine kinase.

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PubMedDate not supplied

[Facilitation phenomenon in the accessory and main olfactory bulbs of the frog Rana temporaria].

It has been demonstrated that facilitation of orthodromic EP by paired electrical stimuli (which was observed earlier in the accessory olfactory bulb of the frog) is also realized in the main olfactory bulb. Facilitation phenomenon in both bulbs is revealed provided the conditioned EP is present before paired stimulation. The accessory olfactory bulb differs from the main one by a longer duration of facilitation. Possible nature of facilitation phenomenon is discussed. It is suggested that differentiation of the olfactory system into the main and accessory ones may be based on differences in the velocity of their activity.

Animals↗
PubMedDate not supplied

[Activity of several membrane-bound creatine kinase isoenzymes in the rabbit myocardium in experimental disruption of coronary circulation].

Activity of CPK isoenzymes, bound with membranes of mitochondria and sarcoplasmic reticulum, was decreased under conditions of acute limitation of rabbit coronary circulation followed by intravenous administration of vasopressin at a dose of 0.5 un per kg of body mass. As a result of this phenomenon the efficient energy-dependent transport of calcium across the membranes of sarcoplasmic reticulum might be impaired with the subsequent development of complex alterations in functional and metabolic parameters, which are found in ischemic myocardium.

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