Laboratory of organic circulation and microhemodynamics

The main goal of the laboratory of organic circulation and microhemodynamics is the research of the regulatory mechanisms of regional venous vessels and their role in capillary fluids exchange in normal and pathological condition (hypoxia, hypo- and hyperthermia, venous insufficiency, arterial hypertension).
The perfusion methods are used in the investigations. Experiments using methods of accumulography, resistography are carried out also. In the laboratory there are precisious perfusions pumps, pressure transducers and flowmeters which allow to estimate the parameters of microcirculation: capillary filtration coefficient, capillary resistance, arterial and venous resistance in the different organs (stomach, kidney, intestine, skeletal muscle). The calcium- endothelium-dependent and biophysical mechanisms of the vascular functions are investigated in the laboratory. The results of our scientific findings are used both in fundamental aspects of physiology of circulation and also in pharmacological investigations.

The regularities were established in interrelationships of hemodynamic indices of the greater and lesser circulation circles as well as the role of resistance of certain regions and the capacitance function of the systemic vascular bed in the formation of the volume of the inflow of venous blood to the heart.

To counterbalance the classical ideas it has been proved that negative pressure in the chest does not play any role in blood return to the heart but is responsible only for phases of the venous circulation fluctuations. The investigations of the department did not confirm the classical hypothesis of the "sticking' role of the right atrium in coming blood to the heart: with the same character of changes of venous return pressure in the right atrium can both increase and decrease. It appeared that changes of blood flow along the interior and posterior vena cava differently participate in the structure of the venous return. Blood flow in the anterior vena cava always grows independent of the character of changes of arterial pressure while in the posterior vena cava it may be different, that also suggests a variable character and complex mechanisms of regulation of the contrary flow along the vena cava in the formation of the venous return. To counterbalance the firmly established opinion in clinical practice it was found that the dynamics of changes of pressure in the right atrium in response to pressor stimuli does not characterize the shifts in the central venous pressure. It was shown that changes to the pressure in the atriums are not similar both in the character and duration, both in the pressor and depressor shifts in hemodynamics.

The evidences of active participation of the venous vessels in the reactions of the cardio-vascular system obtained at the department became a basis for thorough investigation of the fundamental neurohumoral and hemodynamic mechanisms of regulation of the venous part of circulation at the systemic level and for the development of the method of a controlled experiment in the circulation system. These principally new data change the established notion about the mechanisms of the formation of venous return of blood to the heart.