PubMed Health⌕ Search

Biomedical subjects

G R Leont'eva

Publications and source records attributed to G R Leont'eva.

At least 19 recordsLinked to original sources
PubMed1996

[The effect of chemical sympathectomy on the adrenergic innervation of the blood vessels belonging to different organs in salt-sensitive and salt-resistant Dahl-strain rats].

The action of chemical desympathization by 6-hydroxydophamine influencing adrenergic innervation in different organs vessels (mesenterial, renal and femoral) was studied using histochemical fluorescent method in salt susceptible and salt-resistant Dahl rats kept on a low- and high-salt diet. Heterogeneity of adrenergic innervation of different region vessels was established to display and 6-hydroxydophamine caused complete desympathization only in mesenterial artery and in all veins, while in renal artery retained adrenergic plexus its certain branching and femoral artery-in two thirds of its surface. The process of reinnervation in vessels running with different intensity in different animals and in different vessels was found to start in vessels of majority of animals on day 5-6 after the chemical desympathization. 6-hydroxydophamine had greater impact on the vessels of salt-susceptible high salt rat (hypertension) and salt-resistant high-salt-diet (normension) rats. Thus, the state of arterial and venous adrenergic apparatus in hypertension Dahl rats is determined not by the increased blood pressure itself but by the natrium metabolism disturbance.

Adrenergic Fibers↗
PubMed1996

[The structural differences in the mesenteric vessels of rats with spontaneous (SHR) and DOCA-salt hypertension].

Electron microscopy study of different diameter and functional purpose mesenterial arteries revealed that spontaneous and DOCA-saline hypertension cause different ultrastructural changes in all coats with the exception of cranial mesenterial artery, in endotheliocytes of which no changes occurred in spontaneous hypertension. In cranial mesenterial artery both forms of hypertension cause disorder of normal media structure while in ramifications-only in spontaneous hypertension. Cranial mesenterial artery loses is properties in both forms of hypertension and in ramifications, in contrast, growth of elastic material is observed. In media of cranial mesentery artery in both forms intercellular space grows smaller, elastic membrane significantly reduces, myocyte layers go closer and despite their hypertrophy, vascular wall thickness does not change in spontaneous hypertension and increases nonsignificantly in DOCA-saline one. For cranial artery ramifications hypertrophy of vascular wall is characteristic. In spontaneous hypertension sympathetic innervation of branches increases, and in saline vasomotor nerves action turns weaker.

Animals↗
PubMed1994

[The reactivity of the mesenteric arteries and vein to exposure to endogenous noradrenaline in normal rats and rats with DOCA-salt hypertension].

The DOCA-salt hypertension was shown to induce changes of different types in reactivity of the mesenteric artery and vein, acting on the contractility of the vessels rather than on the sensitivity of their receptor apparatus. The observed heterogeneity of the alpha-adrenoreceptors in the artery and the vein suggests that the artery's reactivity is under the control of both humoral and neurogenic factors, whereas the vein's reactivity is neurogenically controlled rather.

Animals↗
PubMed1991

[The activity of the sodium-potassium pump of the mesenteric arteries and veins in normal rats and in DOCA-salt hypertension].

The activity of sodium-potassium pump was studied in mesenteric arteries and veins of rats, as well as its inhibition effect upon catecholamine-induced contractile responses and the time of relaxation of these vessels in normal rats and in those with DOCA-salt hypertension. The activity was measured by 86Rb [correction of 86Rh] up-take. A difference in the ouabain-sensitive take-up was found between arteries and veins. It was higher in normotensive rats' veins than in arteries; in hypertension, the activity of the pump tended to decrease in arteries and sharply increased in veins. Inhibition of the pump with ouabain reduced arteries' contractile responses to noradrenaline and phenylephrine in normotensive animals, whereas in hypertension the effect involved all the types of stimulation leaving intact the contractions of venous vessels. Ouabain increased the period of relaxation of arteries and veins in some types of stimulation in normal as well as in hypertensive rats.

Animals↗
PubMed1988

Sympathetic innervation of blood vessels in rats with aortic constriction hypertension.

The adrenergic innervation of blood vessel wall was studied in various vascular beds of adult rats with experimental hypertension induced by the constriction of the aorta between the origins of both renal arteries. A moderate expansion of body fluids was demonstrated in this hypertensive model. The decrease of the density of adrenergic plexus in the vessel wall as well as the diminished catecholamine fluorescence were found only in renal vessels. These changes were pronounced in the left renal artery and vein even if the left kidney was not subjected to elevated blood pressure. Thus the alteration of vascular adrenergic innervation in hypertensive rats is not a consequence of high blood pressure but it seems to be a part of neurohumoral pathogenetic mechanisms.

Animals↗
PubMed1988

[Versatility of arterial and venous responses to the action of physiologic stimuli in rats with DOCA-salt hypertension].

The reactivity of the rat popliteal, mesenteric and renal arteries and veins to electrical stimulation, noradrenaline, serotonin and potassium chloride in the DOCA-salt hypertension, was studied. The data obtained reveal the organ heterogeneity of the blood vessels contractile responses and the changes of arterial and venous responses in the hypertension, the character and extent of these changes depending on a particular vascular bed and the type of stimulation. Functional changes in hypertensive veins were stronger than in arteries. The artery and vein contractile responses were found to be associated with the external calcium altered in the hypertension. A direct influence of the DOCA and the salt overload on vascular reactivity was studied as well.

Animals↗
PubMed1987

[Adrenergic innervation and reactivity of the blood vessels of different organs].

The structural and functional heterogeneity in rat mesenteric and hind leg arteries has been established. The results of histochemical, biochemical and physiological studies showed the change of adrenergic plexus density, content and ratio of catecholamines and contractility of smooth muscle cells along the superior mesenteric artery. The proximal part of the artery is sparsely innervated and contains only traces of noradrenaline. It demonstrates small contractile response to nerve stimulation, noradrenaline and potassium chloride. Increased nerve density, noradrenaline content and responsiveness has been revealed in the distal part of the artery. The same correlation between the nerve density and vessel reactivity was obtained in hind leg arteries: the more innervated popliteal artery demonstrates more strong contractile response than the femoral artery. It has been also revealed the organ heterogeneity. In general, hind leg arteries are best innervated, contain more catecholamines and demonstrate increased maximal contractility in comparison to mesenteric arteries. The femoral and popliteal arteries have not phasic contractile activity which is very well expressed in the mesenteric ones.

Adrenergic Fibers↗
PubMed1986

The adrenergic innervation of arteries and veins in rats with DOCA-NaCl hypertension: the role of sodium and chloride overload.

The adrenergic innervation of major arteries and veins was examined in DOCA-NaCl hypertensive rats using a histochemical fluorescent technique to detect the intraneuronal catecholamine content. The possible role of sodium and chloride ions was studied in DOCA-treated rats which were fed a low-salt diet which was supplemented with sodium bicarbonate instead of sodium chloride. Focal defects of adrenergic innervation were observed in blood vessels of DOCA-NaCl hypertensive rats. Nevertheless, the degree of these changes differed according to the vascular bed examined. A maximum decrease of the catecholamine content in varicosities of adrenergic terminals was found in the femoral vessels while there were nearly no changes in tail arteries and veins. Adrenergic innervation was usually more impaired in veins than in corresponding arteries of hypertensive animals. Pronounced changes in blood vessels of rats with DOCA-NaCl hypertension contrasted with the maximum alterations observed in those hypertensive DOCA-treated animals which were fed a NaHCO3-supplemented diet. Thus a chloride overload seems to be more important for alteration of adrenergic innervation than the degree of blood pressure elevation or the sodium overload per se.

Animals↗
PubMed1986

The importance of sodium and chloride ions for the development of DOCA-NaCl hypertension: a haemodynamic study.

The role of sodium and its accompanying anion for the development of DOCA-salt hypertension was studied in uninephrectomized DOCA-treated weanling Wistar rats which were fed a diet containing either sodium chloride or sodium bicarbonate (170 mmol/kg). The blood pressure was increased in both groups of rats with sodium overload as compared to rats fed a low-salt diet only. A decreased cardiac output and substantially elevated systemic resistance were demonstrated in both groups of rats with high sodium intake in comparison with rats kept on a low-salt diet. However, these haemodynamic changes were more pronounced in rats with sodium chloride overload than in animals with a high sodium bicarbonate intake. On the other hand, the rigidity of major arteries which was estimated as the pulse pressure/stroke volume ratio, was increased only in rats fed a diet with sodium chloride but not in rats with sodium bicarbonate overload. Thus high sodium intake was responsible for the changes of systemic resistance in DOCA-treated animals and its action was only slightly augmented by a high chloride intake. In contrast to this, the chloride overload seemed to be essential for the induction of increased arterial rigidity.

Animals↗
PubMed1984

[Structural and functional characteristics of arteries and veins in the common frog].

Histochemical, electron-microscopic, pharmacological and physiological studies of structural and functional features of the frog blood vessels revealed a difference in the peripheral neural apparata of different vessels as expressed by different grades of the contractile responses to exogenous substances and electrical stimulation: the better innervated a vessel the better response is mediated by the alpha-adrenoreceptors. The beta-adrenoreceptors have only been found in innervated vessels. The data obtained suggest that vessels of amphibia are in general similar to vessels of vertebrates but the species specifics associated with behaviour and environment of animals determine a number of specific features in structural-functional organization of vessels. The diversity of structure and functioning of blood vessels found in amphibia attests a differentiation of mechanisms of vessel regulation in different areas of the vascular bed.

Acetylcholine↗
PubMed1984

[Development of the neural apparatus of blood vessels in the common frog in ontogenesis].

The neural apparatus of the aorta, abdominal vein, ischiatic, femoral, pulmonary and caudal vessels has been studied histochemically in tadpoles (the 30th-50th stages of development) and in 1-year-old animals. It has been stated for the first time that in the frog, a representative of the Amphibia class, like in mammals and birds, formation of the adrenergic apparatus in various vessels does not take place simultaneously. For instance, the first adrenergic fibers in the hind limb vessels appear much earlier than in other arteries and veins. The process of the adrenergic innervation development and its completion in vessels of various areas is taking its course differently. In the aorta and in the abdominal vein the formation of the adrenergic plexus develops as increasing density and amount of the mediator in the adrenergic fibers and is completed with maturation in an adult animal. In contrast to these vessels, maturation of the adrenergic apparatus in the hind limb arteries and veins takes place during a shorter interval and is completed at the end of metamorphosis AchE-containing fibers are revealed in tadpoles, as well as in a mature frog only in the aortal arc and in the pulmonary artery. In these vessels the development of cholinergic innervation leaves behind that of the adrenergic innervation, as it does in the vessels of Mammalia, and the human subject.

Adrenergic Fibers↗
PubMed1983

[Effect of activation of alpha- and beta-adrenergic receptors, M-cholinergic receptors and H1-histamine receptors on mechanical tension in the frog subclavian vein].

The effects of adrenaline, noradrenaline, isoproterenol, dopamine, histamine, acetylcholine, and serotonin on the wall tension in the isolated frog subclavian vein and modification of these effects by appropriate antagonists were examined. The existence of alpha- and beta-adreno-, M-choline- and H1-histamine receptors was demonstrated. Stimulation of alpha-adreno- and H1-histamine receptors augments and that of beta-adreno- and M-cholinoreceptors diminishes active wall tension in the vein.

Adrenergic Agonists↗
PubMed1981

On the adrenergic system of ganoid fish: the beluga, Huso huso (chondrostei).

The adrenergic system of the beluga, Huso huso, was studied by glyoxylic acid fluorescence histochemistry, analyses of catecholamine content in various organs and studies of the effects of acetylcholine and adrenaline on isolated strip preparations from blood vessels, spleen, atrium and ventricle. Chromaffin cells were found mainly in the walls of the posterior cardinal veins, and to some extent also in the wall of the celiaco-mesenteric artery. The plasma concentration of adrenaline was high enough to affect the contraction force of the isolated atrial and ventricular strips, thus adding an adrenergic component to a possible cholinergic inhibitory vagal control of the heart. Fluorescence histochemistry revealed no direct adrenergic innervation of the heart, but blood vessels in the heart and elsewhere received a rich supply of adrenergic nerve terminals. Adrenaline contracted the celiaco-mesenteric artery and the spleen, and produced positive inotropic effects on the paced atrial and ventricular strip preparations. Acetylcholine contracted the ventral aorta and the celiaco-mesenteric artery, and reduced the contraction force of paced ventricular and, especially, atrial preparations. It is concluded that the beluga has a well developed adrenergic system consisting of both chromaffin cells and adrenergic neurons with varicose nerve terminals of the type found in the higher vertebrates.

Acetylcholine↗