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Biomedical subjects

D P Dvoretskiĭ

Publications and source records attributed to D P Dvoretskiĭ.

At least 19 recordsLinked to original sources
PubMed2005

[The vasomotion characteristics in isolated segment of the tail artery under conditions of slow constant increase of the perfusion pressure].

In vitro, the Wistar rat tail artery segments were perfused with the Crebs-Henselite solution. Under the conditions of perfusion pressure increasing from 0 to 110 mm Hg with the velocity of 5 mm Hg/min, the "diameter-pressure" curves were obtained. Changes in the vessel diameter during increase of pressure in the vessel were accompanied by vasomotions. For the first time, a regularity of the vasomotion direction changes as determined by an increase or decrease of the vessel diameter was established. The increase of the vessel diameter was accompanied by a sequence of its spike-formed decreases, whereas decrease of the vessel diameter was accompanied by a sequence of its spike-formed increases.

Animals↗
PubMed2004

[Responses of isolated arterial segment to a slow changing of perfusion pressure in it].

In in vitro experiments, segments of the Wistar rat tail artery's segments were perfused with the Krebs-Henselite solution. Increase of the perfusion pressure with the velocity of 5 mm Hg/min from 0 to 110 mm Hg with its subsequent drop with the same velocity down to zero showed that, within the limits of the above interval of values of the intravascular pressure, existed a range where two values of the artery diameter corresponded to each established value of the pressure. The data obtained prompt a further deciphering of mechanisms of the mechanogenic regulation of the blood vessels.

Animals↗
PubMed2004

[Effect of low-intensity He-Ne laser irradiation on rat mesenteric microcirculation].

Changes in microcirculation during low-intensity He-Ne laser irradiation were studied by measurement of blood vessels and lymphangions' diameter in anesthetized rat mesentery using method of videomicroscopy in vivo. We demonstrated that the red coherent light induced a significant increase in contractility of vessels' smooth muscle cells. The flow decreased in the mesenteric microvessels during H2O2-mediated oxidant stress was restored after He-Ne laser irradiation.

Animals↗
PubMed2004

[Effects of exogenic noradrenaline and melatonin on the neurogenic vasoreactivity].

The effect of 0.1 microM noradrenaline and melatonin on the response to electrical field stimulation (EFS) of the juvenile rat artery segment was studied. Noradrenaline like melatonin was shown to potentiate the EFS-evoked constriction decreased in the course of experiments or in the acidic solution (pH 6.6), and this potentiation was proportional to the extent of the preceding decrease of the constriction. The effect of these substances was additive. The results suggest that noradrenaline as well as melatonin can serve as a means to restore the diminished neurogenic reactivity of blood vessels.

Animals↗
PubMed2003

[Effect of melatonin on neurogenic vasoreactivity: formation and modulation of the vessel response].

The effect of melatonin (0.1 microM) on the contractile response to electrical field stimulation (EFS) of the juvenile rat tail artery segment was studied. The spontaneous decrease in reactivity of the segment observed in the course of our experiments was accompanied with a melatonin-evoked increase in the reactivity which was proportional to this decrease and was not connected with a sensitization of the segment to the substance. Perfusion of the segment with an acidic solution leads to a more pronounced inhibition of the response as well as to a greater melatonin-evoked protentiation of the response. Noradrenaline-evoked response was not augmented by melatonin. The results suggest that the potentiating effect of melatonin on the EFS-evoked response of the juvenile rat tail artery depends on degree of the change in the artery reactivity and was not due to change in sensitivity of postjunctional membrane to noradrenaline.

Animals↗
PubMed2003

[Effect of infrared low power laser irradiation on blood acid-base balance and respiratory gases tension].

Small volume (0.5 ml) of arterial or venous rat's blood was subjected to impulse LPILR (lambda = 0.89 microns) in the light transparent cuvette. In arterial blood, a decrease of the pO2 (by 15.5 +/- 2.6%) and an increase of the pCO2 (by 22.0 +/- 4.8%) in respect to initial values, were determined. The acid-base shift from 7.39 +/- 0.02 to 7.34 +/- 0.02 was recorded. Only in few experiments, there were changes of pO2, pCO2 and pH in venous blood. Probable mechanism(s) of the mentioned parameters changes are discussed.

Acid-Base Equilibrium↗
PubMed2001

[Response of pial arterioles to alveolar hypercapnia in normotensive and hypertensive rats].

In the WKY rats, a large number of vessels were dilated in response to alveolar hypercapnia, the rest of the vessels remaining unchanged, whereas both vasodilation and vasoconstriction occurred under the same conditions in the SHR rats. The difference seems to be due to biophysical and/or biochemical specifics of the SHR vascular walls and to partially depend on specific features of haemodynamics in pial vascular micromodules in both strains of rats.

Animals↗
PubMed2001

[Contractile function of vessel myocytes: dependence on the stretch magnitude].

The values of the optimal stretch for the maximal responses of the rat mesenteric artery ring to electrical field stimulation (FES) or noradrenaline as well as for the maximal myogenic responses, tone, and maximal changes in these responses produced by low pH and dynamic sinusoidal stretch of the vessel wall were compared. The findings show that the magnitude of stretch corresponding to the maximal effect depend on the character of responses, on the factor, and on the responses occurrence conditions.

Animals↗
PubMed2000

[Reactivity of blood vessels in vitro: the role of perfusate pH and the initial tone of myocytes].

In the rat mesenteric artery ring, acidic solution (pH 7.0) inhibited the electrical field stimulation (EFS)-evoked response in a wide range of stretch. Acidosis potentiated the EFS-evoked constriction of the ring precontracted with 0.5 mu noradrenaline. The EFS dilated rings precontracted with 0.7 mu noradrenaline in control solution but contracted it in the acidic solution. Tone-dependent mechanisms of the acidosis effects on the EFS-evoked responses are discussed.

Animals↗
PubMed1998

[Effect of solution pH on the reactivity of the isolated segment of the rat mesenteric artery subjected stretching of various degree].

Experiments on the rat mesenteric artery's segments at different degrees of its stretching showed no influence of acidosis or alkalosis on the vessel wall tension within a wide range of pH (7.8-6.6). Acidification of the solution (7.0 or 6.6) inhibited the vessel response to noradrenaline or electrical field stimulation (EFS). On the contrary, the acidification potentiated a constriction caused by the EFS at a high level of vascular tone.

Animals↗
PubMed1997

[Regional and local differences in the structural changes in arterial vessels in spontaneously hypertensive rats].

Structural changes of the wall of arteries with different caliber that nourish skeletal muscle, guts and cerebral cortex of 7 months spontaneously hypertensive rats (SHR) were studied. Vessels of ramification order I-II in which significant increase of thickness of media, internal elastic membrane and elastic and collagenic components of the wall occurred were shown to undergo greater changes as compared to normotensive rats (WKR). Popliteal artery displayed myocyte hypertrophy, while hypertrophy and hyperplasty of cells were seen in middle cerebral and anterior mesentric artery. In order III vessels media thickness increased only due to hyperplasty in all regions studied. In order IV vessels almost no prominent structural changes were observed. In was concluded that the nature of alterations in vascular wall of SHR is associated both with peculiarities of regional vascular bed and caliber of branches composing it.

Animals↗
PubMed1995

[The structural component of the vascular adrenoreactivity of the skeletal muscles in normo- and hypertensive rats].

In anesthetized normotensive (WKY) and spontaneously hypertensive (SHR) rats the adrenoreactivity in the maximum dilated vessels of hind leg skeletal muscles was compared. Adrenoreactivity mentioned above has been registered as an amplitude of changes of hydraulic resistance (R), hydrostatic capillary pressure (Pc) and capillary filtration coefficient (CFC) to noradrenaline infusion in the vascular bed of perfused skeletal muscles. Resistance changes were more considerable in experiments on the SHR comparatively to those in the WKY. Changes of CFC as well as Pc in both strains were not statistically differed. The data obtained confirm Folkow's hypothesis about increased adrenoreactivity of the resistance vessels in hypertensive mammals due to structural changes of the vascular bed.

Adrenergic alpha-Agonists↗