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Biomedical subjects

I M Rodionov

Publications and source records attributed to I M Rodionov.

At least 37 records · Page 2Linked to original sources
PubMed1991

[The tonus and relative thickness of the wall of skeletal muscle arterioles].

Inner diameter, absolute and relative wall thickness, and blood flow velocity in arterioles of different branching orders were measured in the rat skeletal (cremaster) muscle. It was found that as the branching order increased the heterogeneity of arterioles with respect to their relative wall thickness also grew. In response to papaverine-induced relaxation of the smooth muscle, there was a direct correlation between vasodilatation and the relative wall thickness. It was shown that a degree of smooth muscle shortening in different arterioles varied widely, the relative wall thickness being a measure (characteristic) of this shortening.

Animals↗
PubMed1991

[A comparison of the efficiency of vasoconstricting effects in spontaneously hypertensive and normotensive rats under different perfusion conditions].

The in vivo biomicroscopy of the m. extensor hallucis proprius revealed thickening of the arterioles walls in spontaneously hypertensive rats (SHRs) as compared with normotensive ones. However, the constrictor responses of the arterioles to standard sympathetic stimulation were 35-50% lesser in the SHRs. The experiments with perfusion of the hind-part of the body revealed reduced responses in the SHRs as well. Therefore, the specifics of morphofunctional structure of the resistive vessels' walls hinders a considerable increase in constrictor responses in the RHRs at a reduced transmural pressure.

Animals↗
PubMed1991

[Changes in the systemic hemodynamics and the vascular bed of the skeletal muscles in rats adapted to hypoxia].

In adult rats after 2 weeks of adaptation to simulated altitude cardiac output was increased by 22% and total peripheral resistance was decreased by the same value. The structural component of peripheral vascular resistance was decreased in rats which were trained 18-20 hrs during 2 weeks and in those trained daily for only 2 hrs. In hypoxically trained rats, the vessel reactivity to sympathetic stimulation was decreased, but to exogenous noradrenaline it was unchanged. Angiogenesis seems to be one of the mechanisms which increase the stability of oxygen transport in microcirculation.

Adaptation, Physiological↗
PubMed1989

[The distribution of blood flow velocity in the terminal bed of the rat mesentery].

Blood flow velocities in microvessels of the rat intestinal mesentery were determined by means of prism-grating method. Mean velocity values in arterioles were 1.9 +/- 0.1, in venules 1.2 +/- 0.2, in capillaries 0.82 +/- 0.06 and in arteriole-venule anastomoses 1.7 +/- 0.2 mm/s. These values do not vary significantly in arterioles with internal diameter from 23.2 to 6.9 mm and in venules from 7.2 to 28.2 mm. The most significant velocity changes appear in the passage of arterioles into capillaries (50%) and between capillaries and venules (40%).

Animals↗
PubMed1988

[Increase in the structural component of the vascular bed resistance in hypertension and its regulatory sequelae].

The increase in structural component of the resistance in hypertension is due mainly to two factors: a decrease in the arteries lumen and a rarefaction of microcirculatory bed, both factors inducing regulatory changes. The first factor increases constrictor effects in hypertensive animals with high intravascular pressure, and reduces the reactivity in low pressure. The rarefaction of microcirculatory bed occurring in various brain areas in hypertensive rats seems to form local foci of hypoxia in neural tissue and to activate sympathetic nervous system through cerebro-ischemic mechanism.

Animals↗
PubMed1988

[Comparative analysis of the efficacy of sympathetic effects on resistive vessels in spontaneously hypertensive and normotensive rats undergoing perfusion at a constant flow rate and under constant pressure].

The authors analyse the efficacy of sympathetic constrictive effects under the conditions of alternative perfusion. A more intensive vasoconstrictive response in perfusion with a constant discharge was observed in spontaneously hypertensive rats as compared to normotensive ones, and in perfusion with a constant pressure the reverse correlation was noted.

Animals↗
PubMed1988

[The role of circular and tangential smooth-muscle fibers in arteriole constriction and closure].

Equations reflecting relationships between the thickness of blood vessel wall (w) and internal radius (r) of the vessel during the process of smooth muscle fiber contraction involved two types of the fibers orientation in vessel wall: at an angle of 45 degrees and 90 degrees to the longitudinal axis of the vessel. Experimental values of w and r were determined on arterioles of the rat mesentery after vasopressin or epinephrine administration. According to the degree of longitudinal and transversal efforts participation in the process of vessel closure, heterogeneity of the arterioles was revealed by comparison of the theoretical and experimental values of w and r. The ability of arterioles for closure did not depend on the initial value of relative vessel wall thickness (w/r).

Animals↗
PubMed1987

[Neurogenic cholinergic dilation observed in isolated vessels of the skeletal muscles of cats (the caudal femoral artery)].

Neuromediated behaviour of feline caudal femoral arteries was studied in vitro. Transmural stimulation of arteries, previously constricted by noradrenaline, caused an up to 58% relaxation of the induced tone. Atropine (10(-5) g/ml) blocked this response by 93%. The removal of endothelium did not affect the magnitude of the response. It is suggested that the caudal femoral artery is an example of a blood vessel which has muscarinic receptors located directly on its smooth muscles.

Animals↗
PubMed1986

[Acetylcholine activation of the sodium pump in frog muscle].

The effect of acetylcholine, ouabain, atropine and d-tubocurarine on the activity of K+, Na+-pump of the frog muscles was studied. Acetylcholine enhanced the activity of K+, Na+-pump, ouabain and atropine preventing the enhancement. D-tubocurarine was ineffective in blocking the ionic pump.

Acetylcholine↗
PubMed1986

[Effect of acetylcholine on the tail artery reaction in rats].

The response to acetylcholine (10(-5) g/ml) was studied on the rat tail artery perfused with Krebs buffer. Perfusion with acetylcholine produced vasodilation (by 69%) in arteries pre-constricted with transmural nerve stimulation. Atropine (10(-6) g/ml) blocked more than 95% of this response. Acetylcholine had a vasodilating effect on arteries pre-constricted with norepinephrine.

Acetylcholine↗
PubMed1985

Rarefication of the arterioles and capillary network in the brain of rats with different forms of hypertension.

The angioarchitecture of rat brain with deoxycorticosterone acetate (DOCA)-saline and renal forms of experimental hypertension were studied and compared with those of normotensive rats. The number of pial arteries of the third, fourth, and fifth order of branching was lower and their diameter smaller in hypertensive animals as compared with controls. In the medulla oblongata, pons, and mesencephalon the number of arterioles was lower and the total length of capillaries per unit volume was shorter in the experimental group. Rarefication of the capillary network was observed also in rats with spontaneous hypertension. Rarefication was found to begin at the earliest stage of developing hypertension. It was observed as soon as 24 hr after the ligation of the remaining kidney in rats with unilateral nephrectomy. A substantial decrease was recorded in the number of pial arteries with preserved lumens. The hypothesis that the rarefaction of the vascular net in the brain may lead to the formation of zones of ischemia is presented here.

Animals↗
PubMed1985

[Effect of adaptation to high altitude hypoxia on the development of structural changes in the resistance vessels of the spontaneously hypertensive rat].

Adaptation to high altitude hypoxia prevents the development of arterial hypertension only in young spontaneously hypertensive rats (SHR) in the pre-hypertension stage. Adult SHR exposed to high altitude hypoxia showed no hypotensive effect. Judging by the experiments with extremities perfusion, the prophylactic effect of high altitude hypoxia in young SHR is associated with an increased number of resistant vessels. The increased ratio of the thickness of the vessel wall to the vascular lumen, however, remains unchanged probably due to the genetically determined development of hypertrophy of vascular smooth muscles.

Adaptation, Physiological↗