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I V Frol'kis

Publications and source records attributed to I V Frol'kis.

At least 19 recordsLinked to original sources
PubMed1989

[The age-related characteristics of the effect of vasopressin on the vascular smooth muscles of the human brain].

Vasopressin was shown to cause a concentration-dependent relaxation of human basilar [correction of bacillary] artery's smooth muscles. In old age, the reactivity of these muscles in decreased and tachyphylaxis to vasopressin disappeared. This seems to be connected with a decrease in the quantity of smooth muscle's V2-inhibitory receptors. Protein kinase C activation does not affect molecular mechanisms of vasopressin action on human basilar [correction of bacillary] artery's smooth muscles. The data obtained suggest vasopressin participation in regulation of human cerebral blood flow and a limitation of adaptive properties of brain vessels' smooth muscles in old age. These factors, apparently, play a role in development of the brain circulation pathology in old men.

Adult↗
PubMed1988

[Role of vasopressin in the development of arterial hypertension and the search for ways to correct it].

The sensitivity of the vessel smooth muscles to vasopressin and their contractile responses were obviously increased in hypertensive rats, whereas the vasopressin inhibitory effect and tachyphylaxis were decreased. These changes seem to be connected with the prevalence of V1-activating over V2-inhibitory vasopressin receptors in hypertensive rats' vessel smooth muscles. Administration of lithium oxybutyrate for 4 weeks normalized central hemodynamics and decreased the sensitivity to vasopressin. The findings suggest a possible role of the inositol pathway in transmission of hormonal signal (vasopressin) to hypertensive rats' vessel smooth muscles as well as participation of vasopressin in pathogenesis of arterial hypertension and the possibility of using lithium oxybutyrate for its correction.

Animals↗
PubMed1987

[Action of vasopressin on the electrical and contractile reactions of vascular smooth muscles in animals of various ages].

Vasopressin action on isolated strips of the femoral artery was studied in mature and old rats. Vasopressin has been shown to depolarize smooth muscle cells (SMC) membranes, causing the tonic contraction of the strips. SMC sensitivity to vasopressin in old animals was increased, electrical and contractile reactions were also enhanced. Peculiar tachyphylaxia in response to vasopressin has been found in SMC of mature animals. In old animals SMC tachyphylaxia was far less expressed than in mature ones. Two types of vasopressin receptors (V1-exciting and V2-inhibitory) in vascular SMC were suggested. Vasopressin does not influence cAMP content of the femoral artery in mature and old animals. Specific features of SMC reactions to vasopressin in old animals may underlie the mechanisms of cardiovascular pathology in old age.

Aging↗
PubMed1983

[Age characteristics of the effect of insulin on smooth muscle cells of the femoral artery].

A study was made of the effects of insulin on smooth muscle cells (SMC) of the femoral artery of rats aged 6-8 and 24-26 months. Insulin hyperpolarized the SMC membrane and diminished the tone of smooth muscles of the vessels. These effects were dependent on the hormone concentration and perfusate temperature. In old animals, the sensitivity of smooth muscles of the vessels to insulin and the response to higher concentrations were reduced. It is believed that the changes described may play a definite role in the mechanisms by which the vascular tone is controlled.

Aging↗
PubMed1981

[Effect of increasing the osmolarity of the extracellular medium on conduction, contractile responses and ultrastructure of vascular muscle].

Increased osmolarity of extracellular milieu suppresses spontaneous contractions of the v. porta smooth muscles first due to disturbance of excitation conduction among the cells necessary for rhythmic contractions of the muscles. Further suppression is due to decrease in the rhythmic electrical activity of the spontaneously active pace-maker smooth muscle cells (SMC). Increased osmolarity alters the SMC reactive ability: their responses to noradrenaline and acetylcholine become less obvious. Increased osmolarity induces lesion of the intercellular contacts, wrinkling of the cells and disorder in the structure of cellular membranes.

Acetylcholine↗
PubMed1980

[Age and the effect of noradrenaline on the physiologic properties and cyclic 3',5'-adenosine monophosphate content of portal vein smooth muscle cells].

With ageing, the threshold doses of noradrenaline necessary for initial electric and contractile responses of the vessel smooth muscle cells, significantly decrease. The levels of cyclic 3'5' adenosinmonophosphorous acid (cAMP) in the portal vein's walls differ insignificantly in adult and old animals. The noradrenaline effect on the portal vein of old animals involves a more obvious increase in the cAMP content. The increased sensitivity of the vessel smooth muscle cells to noradrenaline in old animals seems to be due to the fact that in old animals the adenylatcyclase -- cAMP system responds to lesser amounts of noradrenaline.

Adenylyl Cyclases↗
PubMed1980

[Effect of increasing the osmolarity of the extracellular medium on the ultrastructure of vascular smooth muscle cells].

Changes in the structure of the smooth muscle cells of the portal vein are produced by increasing osmotic pressure (osmolarity) in the extracellular medium. It is demonstrated that under the conditions of the experiment intercellular spaces increase, while the number of close intercellular contacts--nexuses--decrease. The number of micropinocytic vesicles in the areas adjacent the membrane increases, cellular processes and deep invaginations on the cellular surface are formed. In some places the basal membrane loses its integrity. The possible role of the morphological changes for functional shifts occurring in the smooth muscle cells of the portal vein under the conditions of increased osmolarity of the extracellular medium is discussed.

Animals↗
PubMed1980

[Age and features of the functional properties of vascular smooth muscle cells].

Studies on the electric and contractile properties of smooth muscle cells (SMC) of the portal vein of rats aged 6 to 8 months and 26 to 28 months showed that the number of spontaneously active cells, the membrane potential of SMC and action potential amplitude change with age. The force and duration of spontaneous phasic contractions of the strips of test vessels increased. The old animals had a reduction in the maximum rate of contraction and relaxation. These changes play a definite role in the mechanism of vascular tone shifts and in their function during ontogenesis.

Action Potentials↗
PubMed1978

[Bioelectrical properties and ultrastructure of vascular smooth muscle cells in tissue culture].

Intracellular recording was performed in tissue culture of the rabbit vena portae from the smooth muscle cells (SMC) with spontaneous discharges. In inactive SMC the dischartges could be elicited by hyperpolarizing current. The membrane potentials and the input impedance of the SMC decreased with the growth of osmolarity of extracellular medium. The cells were identified as those of smooth muscle on the ground of electronmicroscopic studies. Cellular contacts of nexus type existed between adjacent SMC.

Animals↗
PubMedDate not supplied

[Age-related characteristics of the role of the endothelium in the response of vascular smooth muscles to hormones. The role of ultrastructural changes].

The experiments performed on isolated preparations of femoral artery and aorta of the mature and old rats as well as on those of coronary arteries of adult and old subjects failed to reveal direct participation of endothelium in the realization of insulin and vasopressin effects on the smooth muscles of the vessels studied. However, the endothelium modulated their influence on the vessels in the mature age. The lack of modulating effect of the endothelium in old age may be a result of its structural changes and thickening of a hemato-cellular barrier of the vessel wall observed by electron microscopy.

Adult↗