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Biomedical subjects

T V Lelekova

Publications and source records attributed to T V Lelekova.

At least 19 recordsLinked to original sources
PubMed2005

[Effect of new synthetic anxiolytic selank on gastric wall blood flow and mesenteryc lymphatic vessels contractility in anesthetized rats].

The influence of a new heptapeptide Selank on microcirculation in anesthetized white rats was investigated. Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro) is a new synthetic anxiolytic which exerts obvious antiulcerogenic action and promotes healing of experimental ulcers. Action of the peptide on gastric blood flow in the stomach by using the method ofhydrogenic clearance and Selank action on mesenteric lymphatic contractility by microscopical observation in situ, were studied. Selank fail to influence basal gastric blood flow but it can normalize blood flow reduced by indomethacin. The study of dose-depended of Selank effect on lymphatic vessels contractility showed that its low concentration (10(-12)--10(-14) M) enhanced amplitude and increase frequency of lymphatic vessel contractions which indicates an enhancement of lymphatic flow. The high doses of peptide (10(-6)--10(-10) M) also augmented the contraction amplitude but decreased its frequency. The maintenance of adequate blood flow and lymphatic vessel contractility can be one of the mechanisms of the Selank antiulcerogenic properties.

Animals↗
PubMed2004

Effect of acute hypoxia in pregnant females on contractile activity of lymphatic vessels in the offspring.

Delayed consequences of acute hypoxia were studied in 60-day-old rat pups. The animals were exposed to acute hypobaric hypoxia on day 10 of embryogenesis. The offspring of intact females served as the control. Reactivity of mesenteric lymphatic vessels to norepinephrine was studied by vital microscopy. The frequency and duration of lymphatic vessel contractions in males significantly increased compared to the control. In females the duration of norepinephrine-induced lymphatic vessel contractions increased, while the frequency and amplitude of contractions and basal vascular tone did not differ from the control.

Animals↗
PubMed2004

[Role of adrenoreceptors in the effect of thyroliberin on lymphatic vessels].

Formerly we showed that TRH had simulative effect on mesenteric bovine and rat lymphatic vessels (LV) in very low concentration--10(-12)-10(-18) M. In present paper, participation of LV alpha- and beta-receptors in realization of TRH activity on rat mesenteric lymphatic vessels was studied in situ. Propranolol increased the stimulative effect of TRH, isoproterenol exerted an opposite effect. Phentolamine, prazosin eliminated the simulative effect of TRH, yohimbine resulted in additional gain of effect, which seems to testify 1) presynaptic action of TRH or 2) increase of the output of norepinephrine, which is potentiated by alpha 2-adrenoceptor antagonists. Also the participation of adrenergic receptors in positive chronotropic effects of mesenteric rat LV was studied using the method of selective destruction of dopamine-containing neurons after 6-OHDA infusion. As it occurred, desympathization hindered development of stimulating action of TRH. Thus, the efficiency of TRH as a stimulator of LV is connected with activation of adrenergic mechanisms.

Adrenergic Agonists↗
PubMed2003

Glyprolines and semax prevent stress-induced microcirculatory disturbances in the mesentery.

One-hour immobilization stress considerably disturbed microcirculation in the mesentery: blood flow in small mesenteric vessels decreased or stopped and numerous hemorrhages appeared. Lymphatic vessels lost spontaneous activity and did not respond to norepinephrine. Administration of Semax and glyprolines 1 h before stress decreased the severity of stress-induced microcirculatory disturbances. PGP and GP were most effective in this respect.

Adrenocorticotropic Hormone↗
PubMed2002

[Effect of thyroliberin on contractility and electrical activity of isolated bovine lymphangions].

The role of regulatory peptides is the least explored part in the field of humoral regulation of lymphatics. In this paper we continue a systematic investigation of their effects on the lymphatic vessels of various animals. The effect of thyroliberin was studied on bovine mesenteric lymphatics. The isolated lymphatics contractility and smooth muscle cell electrical activity were investigated. Thyroliberin in ultra low concentrations (1 x 10(-13)-1 x 10(-18) M) exerts a considerable stimulating effect. The mechanism of the theroliberin ultra-low concentrations action and a possibility of the medical usage of the obtained results, are discussed.

Animals↗
PubMed1992

[Thyroliberin: new physiological effects and prospects of clinical use].

In addition to the well-known activities of TRH (stimulation of respiration, antidepressant action, increase of motility, antishock action, therapeutic effects against ataxia, and so forth), some new properties were established. TRH was found (1) to stimulate the contractility of lymph vessels in ultra-low doses and to be useful in the treatment of acute pancreatitis; (2) to normalize cerebral circulation in rats and neonates after asphyxia; (3) to improve the electrophysiological parameters of the retina and pigmented epithelium in rats and man, to exert a long-term positive influence on the health status of patients suffering from senile retinal macular dystrophy; (4) to potentiate the analgesic effect of low doses of morphine in a definite range of doses (analog PR-546). It is of paramount importance that most of the indicated activities of TRH may hold promise for clinical application.

Acute Disease↗
PubMed1992

[The use of thyrotropin-releasing hormone in clinical practice as a lymphatic stimulator in the treatment of acute pancreatitis].

Experiments were conducted to study the modulating effect of thyrotropin-releasing hormone, (TRH) on the contractility of lymphatic vessels of the rat mesenterium. Later, TRH was applied in the clinic in the treatment of edematous and destructive forms of acute pancreatitis in 15 patients. as a result, echoscopy showed diminished edema of the pancreas, amylasemia decreased, the concentration of middle mass molecules in the blood reduced and their transport in the urine intensified. The agent was infused into the veins and into the lymphatic vessels, which allowed its dose to be reduced by half.

Acute Disease↗
PubMed1989

[Effects of femto- and picomolar concentrations of thyroliberin and tuftsin on the contractile activity of lymphatic vessels of the rat mesentery].

Thyrotropin-releasing-hormone (TRH) in concentration from I g/ml to 1.10(-10) micrograms/ml and tuftsin (T) (10 micrograms/ml to 1.10(-6) micrograms/ml) biomicroscopy were used in rats to show the ability to activate the contraction of lymphatic microvascular walls. TRH in used concentrations stimulated spontaneously contractility of lymphatic vessel's walls or evoked its contractility when it was absent. T stopped the contraction of lymphatic microvascular walls and caused the reaction of vasodilatation.

Animals↗
PubMed1987

[Participation of cGMP in inhibitory mechanisms of the center of amphibian lymph hearts].

The effects of cAMP on generation of spontaneous rhythmic activity of lymphatic pacemaker neurons, was studied in fragments of the frog isolated perfused spinal cord. The cGMP depressed both the rhythm of the burst activity and the dibutyril-cAMP effect. The depressive effect of the cGMP was reversibly blocked with furosemide. The data obtained suggest existence of relationship between GABA-ergic inhibition of the pacemaker activity of lymphatic center and the cGMP concentration in pacemaker neurons.

Animals↗
PubMed1985

[Effect of gamma-aminobutyric acid on neurons of the spinal lymphatic center].

In the frog isolated perfused 7-11th spinal cord segments with the lymphatic center, GABA inhibited both the activity of pace-maker neurons and the burst-type activity of lymphatic motoneurons. Picrotoxin, bicuculline, ammonia and furosemide reversibly blocked the inhibition induced with GABA. The data obtained suggest existence of GABA-ergic control of the lymphatic center activity in the 9-11th segments of the spinal cord.

Ammonium Chloride↗
PubMed1983

[Mechanism of the occurrence of evoked motor activity in the lymphatic center of the frog].

In the frog isolated spinal cord, the main parameters of spike activity of the lymphatic center's motoneurons were studied in normal conditions and in altered rhythm of their functioning. Artificial excitation of the lymphatic center by means of stimulation of the dorsal roots, irrespective of the electrical stimuli rate (within the range 1-5 Hz), was shown to induce the same regularities of the evoked motor activity generation in the lymphatic center in the altered rhythm, as in the spontaneous activity of the motoneurons. The main parameters of the evoked activity of motoneurons under these conditions are not significantly dissimilar to the respective parameters of spontaneous activity, either.

Action Potentials↗
PubMed1975

[The effect of acetylcholine on the membrane potential of goldfish retina horizontal cells and the frog electroretinogram].

The effect of acetylcholine was studied as applied to horizontal cells of the goldfish retina and frog electroretinogram ACh (1-10-9--1-10-3 M) depolarized the cells. The highest level of depolarization never reached the O-level of the membrane potential and was approximately equal to the membrane potential in the dark. ACh (1-10-2--5-10-2 M) inhibited b- and d-waves and revealed the stable PIII component. It is supposed that ACh may be a transmitter in retinal outer synpatic layer.

Acetylcholine↗