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Biomedical subjects

O A Shevelev

Publications and source records attributed to O A Shevelev.

At least 19 recordsLinked to original sources
PubMed2005

Uncoupling of afferent and myoelectric reactions in portions of gastroduodenal complex in acute damage period.

In two series of experiments on cats, afferent reactions of organs of the gastroduodenal complex (gastric corpus, pylorus, and duodenal bulb) were studied and myoelectric activity of these portions of the gastroduodenal complex was examined. In each series, only one portion of the gastroduodenal complex was stimulated with electrical pulses. It was found that processes underlying changes in functional heterogeneity and enhancement or moderation of their interrelations in the acute damage period can affect the development of early regional adaptation.

Acute Disease↗
PubMed2003

Role of stomach regions and duodenum in the formation of electrical activity of gastroduodenal complex.

Functional activity of components of the gastroduodenal complex (gastric cardia, gastric corpus, pylorus, and duodenal bulb) was studied in 4 series of acute experiments. One of these regions was subjected to electrical stimulation in each series. Our results suggest that the cardia possesses rhythm-forming properties, the corpus plays a system-organizing role, the pylorus plays a trigger role, and the duodenal bulb produce synchronizing effects.

Animals↗
PubMed2002

Role of serotoninergic structures in coordination of electric activity in the gastroduodenal complex.

Myoelectric activity in various portions of the stomach and duodenum in normal and after vagotomy and intravenous injection of serotonin adipinate was studied in acute experiments on cats. Vagotomy disturbed coordination of myoelectric activity in the stomach and duodenum. Intravenous injection of serotonin adipinate restored coordination and increased myoelectric activity in the stomach, particularly, in the pylorus. Under these conditions the pacemaker of myoelectric activity in the gastric corpus and autonomic regulation of the duodenum were preserved. Intravenous injection of serotonin adipinate most significantly changed myoelectric activity in the pylorus. Myoelectric activity in the cardia increased after vagotomy against the background of serotonin adipinate. Our findings suggest that serotoninergic structures maintain functional heterogeneity of digestive organs and coordinate their interrelationships.

Adipates↗
PubMed2002

Osteovisceral afferent interrelations.

The effects of stimulation of intraosseus receptors on visceral afferent reactions were studied in experiments on anesthetized cats. Stimulation of intraosseus receptors decreased the thresholds of evoked potentials recorded in the cerebral cortex in response to stimulation of the heart, stomach, and duodenum. It was concluded that stimulation of intraosseus receptors during osteopathy (e. g. increased intraosseus pressure) increases sensitivity of visceral sensory systems and can provoke the development of pain syndromes. It is important that visceral pain in such cases should be considered as a symptom of organ pathology, but not as a manifestation of vertebrovisceral syndrome.

Afferent Pathways↗
PubMed1996

[The functional interrelationships of the components of the gastroduodenal complex and its afferent reactions].

The study was undertaken to study the functional relations between the overall electric activities of smooth muscles in 3 gastric portions (cardial and pyloric antrums, and the body of the stomach) and that of duodenal muscles during their direct electric stimulation, followed by the recording of potentials evoked in the feline cerebral cortex. There was an ambiguous correlation of the amplitudes of the electric activity of 4 portions of the gastroduodenal complex during opiate receptor activation and after vagotomy. The central and intraorgan components were found to play a combined role in displaying responses of gastroduodenal smooth muscles to opiate receptor stimulation and block.

Afferent Pathways↗
PubMed1994

[The osteogenic mechanism of vertebrogenic radiculopathies].

Intraosteal block was conducted in 86 patients with pronounced neurological symptoms of lumbar osteochondrosis. To clarify the role of the intraosteal receptors in pathogenesis of the above symptoms and to evaluate the efficacy of the blocks, series of experiments were made on 8 cats. The authors studied evoked potentials in the cerebral cortex and thalamus in response to irritation of the sciatic nerve under the exposure of the sciatic receptors to electrostimulation, intraosteal introduction of physiologic salt solution and trimecaine, electrostimulation following the introduction of the above substances. The pilot experience has been gained on facilitation of afferent current passage from the sciatic nerve under conditions of intraosteal receptor irritation as well as on inhibition of the above effect under anesthetic block of intraosteal receptors. Basing on the above findings, the authors explain osteogenic mechanism of radiculopathy and pathogenicity of the intraosteal blocks.

Adult↗
PubMed1993

[The characteristics of the modulation of the afferent reactions during stimulation of the intraosseous receptors].

Acute tests in mature cats, demonstrated, evoked potentials in the cortex and medial center of the thalamus resulting from test irritation of sciatic nerves and conditioning irritations of intra-osseous receptors. The test proved that electro-irritation of intra-osseous receptors as well as higher intra-osseous pressure caused by the impregnation of physiological solution into the bone facilitated afferent reactions during threshold electrostimulation of sciatic nerves. The results of these experiments were compared to those of clinical monitoring of patients with radicular syndromes of osteochondrosis after intra-osseous blockades which led the authors to suggest a hypothesis about trigger mechanisms of neuralgias, based on segmental alleviation of nociceptive afferentation resulting from overstimulation of intra-osseous receptors.

Afferent Pathways↗
PubMed1992

[Role of the vagus nerve in mechanisms of the modulation of afferent duodenal effects].

The electrostimulation of vagal nerves, the effect of naloxone and atropine on duodenal afferentation by registering evoked potential (EP) at cortex on direct electrostimulation of duodenum have been studied in acute experiments on cats. It has been established that the stimulation of afferent portion of vagal nerves causes the effect of deprivation of EP, whereas the stimulation with certain intensity of efferent portion of vagal nerves intensifies the duodenal afferentation. The effect of afferentation easeness (relief) has been blocked by the application of naloxone 10-20 microgram on duodenal bulbus, but not on it's i. v. injection and without effect on local application of atropine. It is concluded that the role of vagal nerves on the modulation of duodenal nociception is due to the activation of opiate terminals of the efferent vagal nerve portions.

Animals↗
PubMed1991

[Hypothalamo-bulbar regulation of afferent reactions of intact and altered heart].

Afferent reactions of the heart were studied by registration of evoked potentials (EP) in acute experiments on cats. It was established that the hypothalamo-bulbar structures take part in regulation of heart afferentation through depressive effects descending along the system of the vagus nerves. In this case increase of the activity of the posterior hypothalamus in the period of acute myocardial ischemia due to activation of neurons of the motor nucleus of the vagus nerves leads to depression of excitation processes on the neurons of the intracardiac nervous system, while the zones of the anterior hypothalamus exert a relieving effect on heart afferentation.

Afferent Pathways↗
PubMed1990

[The adrenergic regulation of afferent cardiac reactions].

Adrenoreactive structures of the cat heart were studied with the EP technique in normal conditions and in acute damage of the myocardium. The intracardiac adrenergic systems were shown to be able to decrease the myocardium sensory thresholds and thus to aid to an increase in the heart nociceptive sensitivity as well as to take part in the development of intraorganic antinociceptive responses.

Adrenergic Fibers↗
PubMed1990

[Characteristics of cortical representation of the components of the gastroduodenal complex and role of the vagus nerve in the regulation of visceral afferentation].

Evoked potentials were registered at the cortex of both hemispheres of the brain during electrical stimulation of the body of the stomach, pylorus and duodenum pre and post bilateral vagotomy. It has been demonstrated that duodenum is represented at the cortex more widely in comparison with other parts of the gastroduodenal complex. Bilateral vagotomy increases amplitude of the evoked potentials, more substantially at the right hemisphere, that may be connected with enhancement of excitability of the irritating structure by exclusion of the efferent influence of vagal nerves, which take part in the regulation of visceral afferentation at the level of end organ nervous system.

Afferent Pathways↗
PubMed1990

[Characteristics of hemodynamics during correction of cardiac arrhythmia].

In acute experiments on 25 dogs, the automatic system with computerized processing which had been developed by the authors was used to make complex studies of the central hemodynamics, pumping and contractile functions of the myocardium in the presence of complete transverse block during cardiac pacing. With increased hetero- and homeometric regulation during cardiac pacing, normotopic rhythm desynchronization and stimulation rates were found to produce a substantial effect on cardiac performance. Improved hemodynamics in pacing was attended by overload of the left chambers (by 20-60% above the normal values). It was stressed that the choice of the optimal frequency of cardiac pacing should be associated with a conservative performance regimen for the myocardium to meet the body's demands for adequate blood supply.

Animals↗
PubMed1988

[Participation of the opioid-ergic system in the regulation of afferent reactions of the damaged myocardium].

It has been established that in lesion of the myocardium accumulation of huge amount of algesic compounds may cause limitation of the level of cardiac afferentation. Use of naloxone, buterfanol tartrate and D-ala-2-lei-enkephalin prevent the development of the reaction. The possibility of participation of the endogenic cardiac opioids in anti-nociceptive reactions of heart during its lesion is considered.

Animals↗
PubMed1987

[Characteristics of cardiac regulation in ischemic damage to the ventricular myocardium].

The evoked potentials produced by the irritation of the heart sinus node zone in the brain cortex and bradycardia have been registered in 5 to 40-min ischemia of the left and right ventricular myocardium during the electrical stimulation of the vagus. Restricted cardiac afferentation and the heart escape from vagus influences have been revealed at the early stages of ischemia.

Afferent Pathways↗