Contribution of Hydrogen Sulfide to Dilation of Rat Cerebral Arteries after Ischemia/Reperfusion Injury.

The study examined the effect of HS on the tone of cerebral arteries in rats after global cerebral ischemia/reperfusion injury and cooperation between NO and HS in the control over cerebral circulation during the postischemic period. In control sham-operated and in experimental rats with ischemia/reperfusion injury, the diameter of pial arteries was repeatedly measured in vivo under a light microscope after removal of parietal bone and dura mater in 1 h and in 7 days after the surgery. The study established that HS is an important signaling molecule in pial arteries, where it is responsible for vasodilation.

Endothelium-dependent Hyperpolarization-Mediated Relaxation Pathway in Bovine Mesenteric Lymph Nodes.

Endothelium-dependent relaxation mechanisms have been studied in phenylephrine-precontracted capsules of bovine mesenteric lymph nodes studied in vitro. Tetraethylammonium chloride and TRAM-34 in a solution with L-NAME and Indomethacin, which suppress the production NO and prostacyclin of endothelium, increased the tone of the lymph nodes. We believe that in bovine mesenteric lymph nodes, the dilation mechanism is mediated by hyperpolarization of the endothelium, which is associated with activation of large- and intermedium conductance Ca-activated potassium channels.

Effect of Transplantation of Mesenchymal Stem Cells on the Density of Pial Microvascular Network in Spontaneously Hypertensive Rats of Different Age.

Using a TV device for studying microcirculation (×40), we analyzed the density of the whole microvascular network and the density of arterioles in the pia mater of the sensorimotor cortex in SHR rats of different ages (3-4 and 12 months) after intracerebral transplantation of human mesenchymal stem cells. We found that the density of pial microvascular network in SHR rats receiving transplantation of human mesenchymal stem cells increased to a level observed in young Wistar-Kyoto rats.

Changes in Cerebral Blood Flow in the Postischemic Period.

Experiments on Wistar rats showed that blood flow in the cortex and subcortical brain structures was not completely restored within 21 days after transient ischemia caused by bilateral carotid artery occlusion with controlled hypotension. After 7 days of reinfusion, the end-diastolic blood flow velocity increases with simultaneous decrease in pulsation index, which indicates the decrease in peripheral vascular resistance. During the following 14 days, peripheral blood resistance increases, as was seen from the increased peak systolic blood flow velocity, mean blood flow velocity over the heart cycle, and pulsation index.

Influence of High Blood Pressure on Microcirculation in Cerebral Cortex of Young Rats.

We studied the density and structure of the microvascular network of the pia mater, the blood flow rate and oxygen saturation in the sensorimotor cortex of young spontaneously hypertensive rats (SHR). The density of the microvascular network in hypertensive animals was by ~1.4 times lower than in normotensive Wistar-Kyoto rats (control) and arteriolar bed density was lower by ~1.

[THE AGING OF MICROVASCULAR NETWORK FORMED IN CORTEX FOLLOWING INTRACEREBRAL TRANSPLANTATION OF MESENCHYMAL STEM CELLS].

Using a TV device to study microcirculation in brain we found that intracerebral transplantation of mesenchymal stem cells to 12-months old rats led to a significant increase (circa 1,5-fold times) of microvascular density in pia tissue and to increased constriction reactions of pia arterioles in response to noradrenalin application on a brain surface. Both microvascular density and pia arterioles reactivity was completely preserved in aging until 22-24 months.

Postischemic Responsiveness of Pial Vessels to Hypercapnia.

Reactions of pial vessels to hypercapnia were studied in Wistar rats one week after global cerebral ischemia. In ischemic rats, the responsiveness of pial vessels to hypercapnia was diminished, which promoted a decrease in cerebral perfusion reserve. Changes in vascular responsiveness in the arterial and venous subdivisions of the vascular bed were observed and probably resulted from ischemia-provoked down-regulation of the vascular tone.

[Comparative analysis of the potentiative effect of noradrenaline on the neurogenic vasoconstriction diminished by various factors].

The effect of 0.03-1.0 μM noradrenaline on the neurogenic response to electrical field stimulation of the juvenile rat tail artery segment in control conditions, after cooling from 36 to 25 degrees C, and after solution pH decrease from 7.

[Efficacy of mesenchymal stem cells intracerebral transplantation for the correction of age-related cerebral microcirculation alterations in rats].

Using a television-based vital microscopy method and immunohystochemical analysis, we have assessed the effect of intracerebral transplantation of syngeneic mesenchymal stem cells (MSC) on the brain cortex structure and the microcirculation in the pia mater of old rats. Using "open field" system, we have studied the effect of MSC transplantation on position-finding and discovery behavior of older animals. We have found that density of microvascular network of the pia mater increased ca.

Effect of intracerebral transplantation of mesenchymal stem cells on reactivity of pial arterioles in old rats.

Using a TV device for studying microcirculation (×160), we analyzed the responses of arterioles in the pia mater of the sensorimotor cortex in young (2-3 months) and old (22-24 months) rats after local application of a vasoconstrictor (norepinephrine, 10(-6) M) or vasodilator (acetylcholine, 10(-6) M). The responses of the arterioles were evaluated by changes in their diameter and by the number of responding vessels in the field of view. The constrictor responses of the pial arteries to norepinephrine did not significantly differ in intact young and old rats.

[Mesenchymal stem sell donor age effect on the cerebral cortex microvascular net density in old age rats-recipients of transplant].

Male Wistar-Kyoto rats aged 22-24 months were intracerebrally transplanted with syngenic bone marrow mesenchymal stem cells (BM MSC) established from the donor aged 3-4 months and 20-22 months, respectively. Using a TV device to study microcirculation in vivo, we have established that transplantation of BM MSC from young donors increased a density of the microvascular network in the pia mater of the sensorimotor cortex in old rats approximately 1.9-fold, comparing to age-matched controls, while a density of the arteriolar compartment increased approximately 2.

[Potentiative effects of noradrenaline on the neurogenic vasoreactivity diminished by cooling].

The effect of 0.03--1.0 μM noradrenaline on the response to electrical field stimulation of the juvenile rat tail artery segment at 36 degrees C and after cooling to 25 degrees C was studied.

[Age-related changes of microcirculation in pia mater of rats' sensorimotor cortex].

We studied the density of whole microvascular network and separately the density of arterioles in the pia mater of sensorimotor cortex of rats of different ages. Also pial arteriolar reactivity on exposure to norepinephrine or acetylcholine chloride was evaluated. The microvascular density and the arteriolar reactivity in the pia mater were not significantly changed before the age of 12 months.

[The effect of intracerebral mesenchymal stem cells transplantation on the density of microvascular network of the pial matter of the rat brain cortex].

Using a TV installation for studying the microcirculation (with 30-160-fold magnification), the density of microvascular network in the pia matter of the rat brain sensomotor cortex was determined after intracerebral transplantation of mesenchymal stem cells (MSC) or (as control) of the MSC cultivation nutrition medium, or of saline. The results have shown that intracerebral transplantation does not change density of microvascular network in the pia mater of the ipsilateral hemisphere. Transplantation of the MSC led to a 1.

[The effect of noradrenaline on the neurogenic vasoreactivity at various frequencies of the electrical field stimulation].

The effect of 0.03-10.0 microM noradrenaline on the response to electrical field stimulation (EFS) of the juvenile rat tail artery segment was studied.

[The effect of low-intensity red and infrared laser radiation on the rat arterial and deoxygenated blood].

In vitro experiments the effect of low-intensity red or near-infrared laser irradiation on the blood samples (1.5 ml from abdominal aorta of Wistar rats) were studied. The diode laser light (lambda = 650 nm or 808 nm, power density 15.

Noradrenaline can restore decreased neurogenic vasoreactivity.

Experiments on isolated segments of the tail artery from young (aged 4-6 weeks) rats addressed the effects of noradrenaline (0.01-1.0 microM) on the reactions of these segments to stimulation with an electric field in isometric conditions.

Effect of low-intensity laser radiation of the red spectrum on some properties of erythrocytes in Wistar rats.

Laser radiation of different power had various effects on the properties of erythrocytes. An increase in the radiation power from 2.2 to 25 mW/cm2 was accompanied by a decrease in the erythrocyte sedimentation rate and an increase in erythrocyte filtration index.

[Restoring effect of noradrenalne on diminished neurogenic vasoreactivity].

The effect of 0.01-1.0 microM noradrenali on response to electrical field stimulation (EFS) of the juvenile rat tail artery segment was studied.

Differences in adrenoreception in the microcirculatory bed of the pia mater in normotensive and spontaneously hypertensive rats.

Adrenoceptors in pial vascular bed of normotensive Wistar-Kyoto rats are distributed unevenly during stimulation of the superior cervical ganglion, their density was maximum in the 5th-generation arteries. In spontaneously hypertensive rats (SHR) the density of adrenoceptor is lower than in normotensive rats and their number is maximum in the 1st-generation arteries.

Neurogenic vasoconstriction of pial arterial vessels of various branching orders in normotensive and spontaneously hypertensive rats.

Intravital television microscopy was employed to study the reaction of pial arteries in normotensive and spontaneously hypertensive rats to stimulation of the superior cervical ganglion. The amplitude of constrictor response was similar in WKY and SHR animals. Under conditions of normal arterial pressure and arterial hypertension, the maximum constrictor effect was attained due to equal involvement of the arteries from all generations in the normotensive rats and predominant constriction of the precortical arterioles in SHR animals.

[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.

[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.

[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.