Head of the department -

 Vladimir I.Ovsyannikov
Doc. Med. Sci, professor
(812) 234-06-70

Department of visceral systems physiology was organized in 1931 by academician K.M.Bykov, a disciple of I.P. Pavlov.A number of outstanding scientists worked in the Department.

- Academician K.M. Bykov (1896-1959) founded the doctrine of cortical-visceral interrelations,
- V.N. Chernigovsky(1907-1981) initiated investigations on interoceptive physiology,
- Professor A.V. Rikkl (1901-1980) made a significant contribution to the study of intra- and intersystem relations,
- Academician RAMS B.I. Tkachenko (1931 – 2009) started a new trend in home physiology of the cardiovascular system – comparative study of the systemic and regional reactions of arterial and venous vessels to neurohumoral stimulation.

Main stages of research in the Department:

1931-1952 Academician K.M. Bykov develops the theory of cortico-visceral interrelations.
1952-1965 Professor A.V. Rikkl et al. study neuro-humoral mechanisms of vegetative functions interralationship.
1965-2010 Academician RAMS B.I. Tkachenko et al. study the functional integration of resistance and capacitance vessels, and filtration-absorption balance in the capillary bed.

● Use of new methodical approaches (perfusion of vascular bed under constant flow or pressure) has allowed to investigate reactions of arterial and venous vessels of skeletal muscle and various visceral organs in the dynamics and to estimate efficiency of reflex influences on them. It is established that the main role in the shifts of total peripheral resistance in systemic reactions belongs to arterial vessels of skeletal muscles and intestines.
● Active role of venous vessels in regulation of transcapillary fluid exchange and blood return to the heart is proved: intramural venous vessels, creating postcapillary resistance, influence capillary pressure, and changing capacity, form adequate blood return to the heart.
● New functional classification and the scheme of blood circulation system have been offered.
● Concept is put forward according to which distinctive feature of venous vessels in comparison with arterial ones is that only resistance is inherent in the last, and the venous vessels possess both resistance, and capacitance. The hypothesis has been put forward according to which local constriction of sphincterlike sites of venules and small veins is capable to cause passive dilation of prelying sites of venous vascular bed and consequent retention of blood in them. With the method of venous resistograpy it has been established that changes of resistance in a venous part of visceral vascular bed are capable to shift essentially the level of capillary pressure. It has been shown that endothelium of brain venous vessels is a component of blood-brain barrier. Significant changes of resistance, capacitance and fluid-exchange functions of regional vessels have been revealed in the conditions of a high-mountainous hypoxemia: increase of arterial and venous vessel reactivity to adrenergic vasoconstrictor stimulus in parallel with increase of the coefficient of capillary filtration. It has been established that wave characteristics of blood-flow and pulse pressure are significant in providing of arterial and venous vessel function.
● Correlation of venous return and cardiac output with pulmonary hemodynamics in transition regime of cardiovascular system has been established. As a result of research carried out by using the method of controllable experiment, the concept of two-component structure of pressor reactions of blood circulatory system has been put forward: the initial phase of the systemic arterial pressure rise is mainly a result of increase of the total peripheral resistance, and its subsequent maintenance at high level is a result of venous return and cardiac output increase.
● Elaboration of unique implantable gages for registration of pressure and a blood-flow changes has allowed to reveal character of cardiovascular and respiratory system interrelations under gravitational loadings in chronic experiment.

1980-2010, Professor V.I. Ovsyannikov et al. investigate mechanisms of integration of neuromediators and hormones in the gastrointestinal tract.
● The use of neuropharmacological analysis of the experiments on intact animals has allowed to prove the existence of the earlier unknown functionally significant mechanism of integration of adrenergic and cholinergic influences in regulation of the gastrointestinal motor function. The concept of double adrenergic control of cholinergic neurons of the enteric nervous system has been put forward.
● It is established that psychogenic stress is accompanied by discoordination of contractile activity of a stomach and a duodenum that causes the duodeno-gastric reflux and erosive damage of the gastric mucosa. This functional asymmetry is considered as prenosological stage of the gastric ulcerative disease.
● With repeated application of stress stimulus previously unknown dyskinesia has been revealed, which is manifested in poststress period by sustainable increase of contractile activity of the colon in its entirety, this reaction being the cause of disturbance of the normal relations between contracted and relaxed zones of the colon necessary for adequate chyme transit.

In 2010, Professor V.I. Ovsyannikov headed the Department of visceral systems physiology comprising 2 subdivisions: Laboratory of systemic and regional blood circulation, and Laboratory of adaptive regulation of visceral functions.

At present the main trend of study in the Department are «The mechanisms of adaptive regulation of visceral functions», aimed to reveal possible ways of realization of the stress pathogenic potential in the development of arterial hypertension and ulcerative disease of the gastrointestinal tract.

The main results of studies performed by the Department in this field:
●The mechanisms of inhibitory and stimulatory changes of contractile activity in all parts of the gastrointestinal tract at psychogenic stress have been clarified.
●Proximal-distal gradient of stimulatory and inhibitory mechanisms in the gastrointestinal tract has been revealed.
● It has been shown that strengthening of contractile activity in proximal and distal part of duodenum under stress has various mechanisms.
● According to our priority data the period of stress is characterized by prevalence of inhibitory processes in the enteric nervous system, and there is an explosively rise of cholinergic activity in post-stress period.
● Chronophysiological approach in study of the gastrointestinal functions has allowed to make conclusion significant for the practical medicine: optimization of the motor and evacuatory function of the gastrointestinal tract is only possible if the principle of regularity in the circadian activity of visceral systems is followed.