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Biomedical subjects

G G Kniazev

Publications and source records attributed to G G Kniazev.

18 recordsLinked to original sources
PubMed1997

[Structural changes in the tissues of white rats after capsaicin administration].

Tissue structure of albino rat lung, skin and cornea changing after administration of capsaicin (neurotoxin isolated from red pepper) was studied using light and electron microscope. 5 mg/kg dose causes tissue swelling and microcirculatory bed reaction. 200 mg/kg dose leads to more significant dystrophic tissue alterations. Fibrosclerosis signs were found in certain cases. Microcirculatory disorders are proposed as the main reason for tissue structure alterations observed, although the mechanism of their development is still unclear.

Animals↗
PubMed1989

[Mechanism of the development of neuroparalytic keratitis].

There is a hypothesis that for appearance of the neuroparalytic keratitis a decisive role has cessation of discharge of trophic factors, demonstrating a polypeptide nature. from sensitive nervous endings. In order to check the hypothesis, deafferentation of the eye has been performed by means of electrocoagulation of the trigeminal sensitive nucleus in the medulla oblongata. Despite the fact that as a result of the operation connection of the sensitive cells with the periphery is preserved, the neuroparalytic keratitis occurs at the same time, as after sectioning the trigeminal nerve branching. The suggestion on excessive discharge of catecholamines from the sympathetic terminals as the cause of deafferentational disorders is not confirmed. The eye desympathization does not prevent appearance of the neuroparalytic keratitis. It is supposed that discontinue of information current to the center makes regulation of the peripheral tissues homeostasis impossible, that is the cause of the trophic disturbance.

Animals↗
PubMed1988

[Effect of deafferentation of the liver on hepatocytes located in various parts of the hepatic lobule].

Taking into account the data on functional heterogeneity of hepatocytes, situating in various parts of the hepatic lobule, influence of deafferentation of the cat liver on changes in the size of hepatocytes and their nuclei, as well as contents of glycogen and nucleic acids in their cytoplasm have been investigated. The greatest decrease of the glycogen contents and the greatest increase of the nucleic acids and the nuclei volume take place in hepatocytes, situating around the central vein.

Afferent Pathways↗
PubMed1981

[Emotional-defensive behavior and noradrenergic forebrain structures].

Conditioned avoidance responses in rats increase the noradrenaline expenditure in forebrain. The animals which reproduce no conditioned response after learning as well as the animals with ECS-induced retrograde amnesia preserve the noradrenergic terminals reaction as well as the emotional component of the conditioned response. The extinction of the emotional component by repeated testing or diazepam administration decreases the noradrenergic terminals activation. The data obtained support the view of the noradrenergic system participation in emotional--defensive behaviour.

Amnesia, Retrograde↗
PubMed1977

[Quantitative assessment of catecholamine fluorescence detected by the Falck method].

While using Falck's method, a number of simple and handy additional ways were suggested to carry on quantitative estimation of the fluorescence change of noradrenergic and dopaminergic terminals in a number of nuclei of the central nervous system. A device was used, which allows to obtain samples of brain of a given size and in a definite plane. The method we used makes it possible to treat simultaneously a great number of material at all the stages of work. Fluorescence intensity was measured by means of fluorometric device with the stop of a large diameter. Tests with the substances lowering the content of catecholamines showed that at the content of catecholamine less than 60% one can observe linear dependance between fluorescence intensity and the content of catecholamine in tissues. In the sphere of high concentrations such linearity does not exist.

Animals↗
PubMed1977

[Use of disulfiram in a histochemical study of the influence of different stimuli on the concentration of noradrenaline in brain structures].

With the help of the histochemical fluorescence method the changes in noradrenaline fluorescence of nuc. septi lateralis, nuc. interstitialis striae terminalis and nuc. preoticus medialis during conditioning and unconditioned stimulation were studied. In 135 disulfiram pretreated rats the depletion of noradrenaline fluorescence in the investigated structures was found after electro-stimulation of feet during 5 min., 1 and 2 hours, open-field behavior and reproduction of a conditioned avoidance response. Twelve hours after disulphiram administration the suppression of the open-field behavior and reproduction of the conditioned avoidance response as well as the depletion of noradrenaline fluorescence in the investigated structures were detected.

Animals↗
PubMed1976

[An analysis of participation of central noradrenergic structures in the process of memory trace reproduction].

Variations of the noradrenaline content in noradrenergic terminals of different nuclei of the limbic system and the anterior hypothalamus were studied by the limuniscent histochemical method in the course of reproduction of a series of conditioned reflex reacitions in male Wistar rats. Both in reproduction of a conditioned passive avoiding responce and in training with inevitable conditioned reinforcement, a decrease of the noradrenaline content was found as compared with the control level. A lesser decrease was observed both in the animals that had been trained but did not reproduce the relfex reaction, and in the trained animals after repeated testing for 4 days following the training. The reproduction of the conditioned active avoiding response in shuttle box did not entail variations in the noradrenaline content.

Animals↗
PubMed1975

[Analysis of the participation of rat brain noradrenergic terminals in elaboration of conditioned passive avoidance response].

A change in a noradrenaline concentration in the noradrenergic terminals was investigated by the fluorescent histochemical method in pars ventralis nuc. interstitialis striae terminalis, nuc. septi lateralis and in nuc. preopticus medialis of male Wistar rats in the process of reproduction of conditioned passive avoidance response. In all the investigated structures of the preliminarily trained animals the reproduction of a conditioned response (without any electrical stimulation) led to a statistically reliable decrease in the noradrenaline concentration. The data obtained testified to the participation of the noradrenergic brain system in the reproductive process of the conditioned passive avoidance response.

Animals↗
PubMedDate not supplied

[The microcirculatory disorders in deafferentation of the eye].

Microcirculatory disorders occurring in the eye of rats in the early period after deafferentation were studied. The blood flow in the iridic vessels became slower and permeability of the eye vessels was disturbed in the first hours and minutes after retrobulbar injection of the anesthetic trimecaine. Similar changes were encountered in division of the trigeminal nerve branches and in electrocoagulation of the sensory nucleus of the trigeminal nerve as well as in venous congestion induced by applying a ligature to the veins of the eyeball. All these procedures led to corneal edema and development of an inflammatory process. Eye sympathectomy caused neither disorders of vascular permeability nor keratitis. Changes of vascular permeability and tissue edema occurring in the early periods after deafferentation are probably among the causes of the subsequent dystrophic disorders in the peripheral tissue.

Afferent Pathways↗
PubMedDate not supplied

[Development of neuroparalytic keratitis after retrobulbar administration of trimecaine].

The blood flow in the iris vessels slowed down and the vessel permeability increased early after a retrobulbar injection of trimecaine, a local anesthetic, this resulting in the development of tissue edema. Two days later neuroparalytic keratitis developed. The authors suppose that early vascular disorders resultant from blocking of the sensitive nerves are among the causes responsible for later changes in the corneal trophics.

Acetanilides↗
PubMedDate not supplied

[Reaction of cells of subcutaneous connective tissue to the activation and blockade of the peptidergic system].

Changes in the quantitative composition of subcutaneous connective tissue cells were examined after activation and blockade of the peripheral peptidergic system with capsaicin. The activating dose (5 mg/kg) of the agent was found to increase the quantity of mast cells in the subcutaneous connective tissue. Its toxic dose (200 mg/kg) elevated the histiocytic and fibroblastic index while the number of mast cells reduced. The same reaction was seen in surgically impaired tissue innervation. It is concluded that peptidergic capsaicin-sensitive neurons play a role in the development of neurogenic dystrophy and this process involves connective tissue cell elements.

Animals↗