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Biomedical subjects

A V Samoĭlenko

Publications and source records attributed to A V Samoĭlenko.

At least 19 recordsLinked to original sources
PubMed2001

[Efficacy of neurogenic and humoral stimuli in venous return in cats].

Humoral stimuli (i.v. adrenaline) proved to exert a greater effect on venous return in anesthetized cats than neurogenic those (electrical stimulation of either brain stem or femoral nerve). The part of cardiac output, however, in arterial blood shifts was the same. The latter finding is, probably, due to a discrepancy between changes occurring in the venous return and cardiac output caused by blood detention within the lung circulation as well as by an elevation of the blood pressure.

Afferent Pathways↗
PubMed2000

[Changes in the venous vessels capacitance in the cat forepaw in response to neurohumoral stimuli].

The trend in changes of the cat forepaw vessels' capacity was found to practically not differ from the trend in shifts in the vena cava anterior basin's capacity: in both areas the capacity decreases in response to pressor neurogenic stimuli and decreases or increases under the effects of pressor and depressor humoral stimuli. The data obtained suggest that the trend in shifts of the vena cava anterior basin's capacity under the effects of pressor humoral stimuli mainly depends on the skin-muscular area's vessels, whereas the trend in shifts of the vena cava anterior basin's capacity under the effects of depressor humoral stimuli depends, apparently, on the shifts in the brain vessels' capacity function.

Acetylcholine↗
PubMed1998

[Quantitative evaluation of participation of the cardiac and vascular components in arterial pressure changes].

Under the effect of adrenaline upon the circulation system, vascular components of the blood pressure (BP) was shown to provide 75% of the maximal rise of the BP and the cardiac component--25%, whereas in response to noradrenaline the values were 62% and 38%, resp., in cats. In further development of systemic responses the role of cardiac component is enhanced whereas the role of vascular component becomes limited. Participation of the vascular component alone in systemic shift induced with catecholamines, under conditions of stabilised cardiac output, decreases the duration of the BP rise, whereas a combined rise of peripheral resistance and cardiac output in natural circulation provides an elongation of the BP changes.

Animals↗
PubMed1990

[The organic macro- and microhemodynamics and the systemic circulation under the combined action of hypoxia and hypothermia].

In regimen of the constant blood flow perfusion of shank and small intestine of cat combined effect of hypoxia (10% O2 in N2) and hypothermia (about 30 degrees C) involved a decrease in precapillary resistance, an increase in capillary filtration coefficient in both vascular regions, an increase in postcapillary resistance and in mean capillary pressure in the intestine, and their decrease in the shank. In hypothermia, the hypoxic stimulus induced insignificant shifts in all the parameters under study in both organs. Dependence of hypoxic changes of macro- and microhemodynamics on the activity of adrenergic receptors in the cooled organism was studied on decentralized shank of cat. After cooling of cat and blockade of alpha-adrenoreceptors hypoxic hypoxia caused much greater reduction of precapillary resistance of shank, more striking (by 3 times) increase of capillary filtration coefficient and the increase of capillary pressure and postcapillary resistance in contrast with their decrease to hypoxia under hypothermia before alpha-blockade. Beta-adrenoreceptor blockade had no influence on the changes of the resistance and exchange function of skeletal muscle (shank) blood vessels evoked by hypoxia under cooling. Systemic arterial pressure are diminished during hypoxia under the normothermic conditions of animals. Such kind shifts caused especially by the decreasing of the total peripheral resistance; cardiac output are small raised in this situation. But combined influence of hypoxia and hypothermia evoked the pressor shifts of the systemic arterial pressure because of less decrease of total peripheral resistance and more remarkable rise of cardiac output. Hypoxic stimulus caused both in normothermia and hypothermia conditions caused the rising of venous return.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[The dependence of the hemodynamic shifts in the systemic arterial and venous vascular beds on the degree of change in the arterial pressure under the action of vasoactive substances].

The participation of hemodynamic parameters in formation of systemic pressor displacement due to action of norepinephrine and angiotensin was shown in acute experiments in cats. An arterial pressure rise by 15 +/- 2% and 25 +/- 3% depended on total peripheral resistance and cardiac output enhancement. The maximal arterial pressure rise only depended on total peripheral resistance increase. The reduction of venous return resulted from a decrease of the blood flow in v. cava posterior whereas the blood stream in v. cava anterior increased. Depressor actions of acetylcholine and histamine were enhanced owing to a fall in the vessels resistance.

Acetylcholine↗
PubMed1987

[Effect of the thoracic pumping function on venous return in chronic experiments].

In cats with implanted ultrasonic transducers, interrelationships between phasic oscillations of the blood flow in posterior v. cava due to the chest sucking function and changes of intrapleural pressure, were studied. Linear dependence of shifts of these parameters was only observed in an increased pressure and respective drop in venous blood flow. The dependence was absent in drop of the pressure and increase of venous blood flow. The ratio of the intrapleural pressure shift to magnitude of phasic changes of the blood flow in the posterior v. cava (the pumping coefficient) is suggested for estimation of effect of the chest sucking function upon the venous outflow and for relative estimation of rigidity of the vascular bed's venous portion.

Animals↗
PubMed1987

[Changes in systemic hemodynamics during exposure of the cooled body to hypoxia].

In cats with normal body temperature, hypoxia (10% O2 in nitrogen) induced depressor shifts of the arterial pressure due to a drop of the general peripheral resistance, whereas in cooling of the organism to +30 degrees C a slight increase of the arterial pressure occurred. Hypothermia was found to reduce the degree of increase in the venous return in response to a hypoxic stimulus.

Animals↗
PubMed1986

[Systemic hemodynamic shifts in the arterial and venous portions of the vascular bed in hypoxia].

A reduction of total peripheral resistance is of a major importance for depressor shifts of arterial pressure in moderate hypoxia. The hypoxic stimulus induces a deficiency of increment in cardiac output shifts as compared with venous return. An increment of venous return and cardiac output suggests that the compensation for the depressor shifts induced with the lack of O2 in air and blood, occurs on account of flow induces of the circulation system.

Animals↗
PubMed1983

[Study of the role of the venous return in pressor changes in the systemic hemodynamics by the means of the automatic regulation of its value].

Feed-back experiments with catecholamine-induced pressor changes of arterial pressure (AP) aided to study possible contribution of the venous return changes in cats. Preliminary recorded changes were reproduced with the aid of electronic control of perfusion pump connected with extracorporeal reservoir and venous portion of vascular bed. The reproduced changes of venous return corresponded to those occurring under action of catecholamines. The same maximal increase of AP (by 50%) could be obtained by means of increasing the venous return either by 1/6 with adrenaline (A) or by 1/10 with noradrenaline (NA). Maintaining of the increased AP involves to a greater extent participation of the above parameters in systemic shifts; in response to A 1/2 and in response to NA 1/3 of the pressor response can be maintained by an increase in the venous return. The quantitative contribution of the vascular component (total peripheral resistance) to pressor shifts of AP under the catecholamines action is greater than that of the cardiac component, particularly in response to NA.

Animals↗
PubMed1981

[Blood flow in the inferior vena cava measured by a Doppler ultrasound flowmeter in chronic experiments on cats].

Supercound Doppler's transducers indwelled in the cat v. cava posterior revealed that the higher blood flow values in chronic experiments as compared to acute ones were due to the effect of the chest suction action on the blood flow. The phasic changes of the venous blood flow occurring at resting and under various effects were related to respiration and heart activity, the respiratory component being more obvious than the cardiac one. A significant correlation existed between the mean value of the blood flow in the v. cava posterior and the respiratory changes of the blood flow amplitude.

Animals↗