[Ultrastructural changes in the right atrium in rats during E. coli lipopolysaccharide-induced systemic inflammation].

In acute experiments on rats, systemic inflammation was induced by intraperitoneal E. coli lipopolysaccharide (LPS) injection that in a dose of 5 microg/kg caused an increase in rectal temperature by 1.0 +/- 0.3 degrees C and 2.5 +/- 0.2 degrees C, respectively, at thermobox temperature of 22 degrees C and 35 degrees C, and in a dose of 1000 microg/kg caused its decrease by 1.7 +/- 0.6 degrees C at 22 degrees C and increase by 0.4 +/- 0.1 degrees C at 35 degrees C. In all the animals, cardiomyocytes demonstrated a functional tension which appeared as a growing number of mitochondria, nuclear pores and cisterns of the endoplasmic reticulum. In the microvessels, when both LPS doses were administered, leukocyte and macrophage adhesion to endotheliocyte membrane was demonstrated. After LPS injection in a dose of 1000 microg/kg, numerous large secretory granules were observed under the sarcolemma close to the microvessels in hormone-producing cardiomyocytes, containing natriuretic hormone. Contractile cardiomyocytes showed signs of early-stage apoptosis (accumulation of small mitochondria with electrone dense matrix, cytoplasmic invagination into the nucleus, formation of apoptotic bodies). LPS in a dose of 1000 microg/kg at thermobox temperature of 35 degrees C induced changes in some cardiomyocytes with the signs of late-stage apoptosis (condensed nucleus and cytoplasm).

[Effects of antiorthostatic hypokinesia on blood levels of interleukine-1beta and interleukine-6 in primates].

Investigations with Macaca mulatta of 4-5 yrs. of age with the body mass of 4.5-6.5 kg showed that 10 days of tilting with the head end at .5 degrees reduced body temperature but not levels of interleukine-1beta and interleukine-6 in blood plasma. On the next days after return of animals to cages IL-6 was found to increase sharply in more than 10 times. On subsequent 4 days both IL -1beta and IL-6 were within the normal range.

The effects of activation and blockade of central P2X receptors on body temperature.

The aim of the present work was to identify the role of ATP acting on specific P2X receptors in the central mechanisms of thermoregulation. Immunohistochemical studies demonstrated that brainstem structures involved in controlling body temperature contained large number of nerve cells bearing P2X ATP receptors. Experiments on conscious rats involving intracerebroventricular administration of an ATP analog and P2X antagonists showed that both activation and blockade of central P2X receptors produced marked changes in body temperature. Analysis of the effects of these substances provided grounds for suggesting that ATP acting on P2X receptors fulfils an important function in the mechanisms of transmitting afferent information from peripheral thermal receptors to thermoregulatory centers in the brainstem with responsibility for heat loss, while in pyrogen-induced fever ATP acting on these receptors may be involved in the activity of the endogenous antipyretic system.

[Effect of activation and blockade of central P2X receptors on body temperature]. / Vliianie aktivatsii i blokady tsentral'nykh P2X-retseptorov na temperaturu tela.

The aim of the present study was to elucidate the role of extracellular ATP acting on specific P2X receptors in the central mechanisms of thermoregulation. Using immunohistochemistry methods, it was found that the brainstem structures involved in the body temperature regulation contain a large number of nerve cells which possess P2X receptors for ATP. Experiments with intracerebroventricular application of a stable ATP analogue and P2X receptor antagonists to conscious rats showed that both activation and blockade of central P2X receptors resulted in marked changes in body temperature. Analysis of the effects of these agents suggests that ATP by acting on P2X receptors performs an important function in the mechanisms of transmission of afferent information coming from peripheral thermoreceptors to the brainstem thermoregulatory centres responsible for heat loss, and during pyrogen-induced fever can be involved in the action of the endogenous antipyretic system.

[Evaluation of technogenic radiation exposures from ecological and physiological points of view]. / Otsenka tekhnogennykh radiatsionnykh vozdeistvii s ékologo-fiziologicheskikh pozitsii.

Many years' experience with complex supervision of the environmental radiation situation, the specific features of the population's physiological and health status after radiation accidents (the Chernobyl, Kyshtym and other accidents). The paper emphasized the necessity of having a knowledge of the specific features of the influence of a radiation factor (and its components) on establishing the radiation dose for the population due to the environmental peculiarities of the radiation background in different regions and abnormal zones of the Earth. The paper provides evidence for the need to apply an environmental and physiological approach to working out the standards of radiation doses for the inhabitants of post-accident polluted areas. To this end, a concept of the regional standard of exposure is proposed for different regions of the Earth with regard to the specific natural radiation background, technogenic and medical "additives" on making diagnostic and therapeutical efforts by using X-rays and radiation therapy. A new concept is offered to develop the life-support systems in the areas exposed to radiation contamination, whose main goal is to minimize radiation exposures with regard of data on each area-specific data on the regional standard of the pre-accident radiation background, technogenic background, medical additives and prediction of future radiation doses. Exposure of the population to radiation is minimized by reasonably operating its components and making special life regimens in the contaminated areas.

[Neurotransmitter balance in the CNS structure as effected by the combination of ionizing radiation and various doses of lead acetate]. / Neiromediatornyi balans v strukturakh TsNS pri sochetannom vozdeistvii ioniziruiushchei radiatsii i razlichnykh doz atsetata svintsa.

In experiments with mature Wistar male rats exposed to 25- and 50-fold fractionated doses of external X-ray radiation (0.5 Gy) and daily probe-assisted administration of plumbum acetate (100, 10, 5 mg/kg), similar, but differently marked changes in transmitter relationship in some CNS structures resembling the earlier found neurotransmitter disbalance during chronic stress of different ethiology were revealed. Combined exposure to plumbum and radiation led to more sustained and prolonged disorders to transmitter relationship associated with a sharp decrease in specific binding of corticosterone in CNS glucocorticoid-sensitive structures.

[Function of the hypothalamus-thyroid system long after radiation and neurotropin correction of the disorders detected]. / Funktsiia sistemy gipotalamus-shchitovidnaia zheleza v otdalennye sroki posle oblucheniia i korrektsiia vyiavlennykh narushenii neirotropinom.

In experiments on Wistar male rats exposed to single X-ray radiation 0.5 Gy and combination of X-ray 0.5 Gy and 131I 6.5 microCi/kg inhibition of activity of excitatory and inhibitory neurotransmitter processes in the mediobasal hypothalamus was observed 6 months after radiation. This was accompanied by a prolonged hypofunction of the thyroid gland related to disorders with glandular stromal follicles and secretion of hormones into the bloodstream. Application of neurotropin that normalizes to a certain extent the transmitter relationship in the hypothalamus does not act positively on the thyroid functional activity. All this indicates a necessity of combined correction of the disorders found not only with neurotropic drugs but also with directional therapy of the affected organs and systems.

[Modifying effects of neurotropin on post-radiation disorders of neuromediator processes in the autonomic function regulation centers]. / Modifitsiruiuschchie éffekty neirotropina na postluchevye narusheniianeiromediatornykh protsessov v tsentrakh reguliatsii vegetativnykh funktsii.

In experiments on Wistar rats, it was shown that 6 months after exposure to ionizing radiation (X-radiation 0.5 Gy and intraperitoneal 131I 6.5 mCu/kg) the hypothyroid state was accompanied by changes in inhibitory and excitatory mediation that are characteristic of chronic radiation stress in cerebral structures responsible for regulation of autonomic and animal functions and a relative deficiency of the hypothalamopituitary-adrenocortical axis. Application of therapeutic doses of neurotropin 3 months after radiation levelled the pattern of chronic radiation stress and diencephalic disorders that underlie disturbances of some systemic functions of the organism.

[Ultramicroscopic organization of the vascular plexus in the rabbit cerebral lateral ventricles and its changes under the effect of pyrogens]. / Ul'tramikroskopicheskaia organizatsiia sosudistogo spleteniia bokovykh zheludochkov mozga krolika i ee izmeneniia pri deistvii pirogenov.

By means of electron microscopical methods organization of various components of the vascular plexus in the rabbit cerebral lateral ventricles--ependymal and supraependymal cells, as well as capillaries, making the base of the hemato-encephalic and hemato-liquor barriers of the plexus have been studied. Injection of bacterial pyrogen (pyrogenal) to the animals is accompanied with an increasing permeability in the barriers of the vascular plexus for certain blood cells (lymphocytes, monocytes), their activation and transformation into plasma cells and macrophages. Under pyrogenal effect in the ventricle cavities activation of the supraependymal cells and intensification of their interaction with the underlying ependyma take place. In the ependymal layer local dilatation of intercellular spaces and intensification of exocytic processes are observed. The changes revealed demonstrate an active reaction of some elements of the vascular plexus to fever, dependent on injection of the bacterial pyrogens into the organism.

[Ultrastructural organization of the hypothalamic medial preoptic area and its changes under the effect of pyrogens]. / Ul'trastrukturnaia organizatsiia medial'noi preopticheskoi oblasti gipotalamusa i ee izmeneniia pri deistvii pirogenov.

In order to study structural bases of central mechanisms of thermoregulation, a comparative electron microscopic analysis of various cellular groups in one of thermosensitive zones of the cat hypothalamic area--the medial preoptic area--have been carried out under conditions of experimental fever. The latter is produced by injection of pyrogen of bacterial origin--pyrogenal--to the animals. Pyrogenal, increasing the body temperature, produces a stimulatory effect on various cellular elements, first of all on leucocytes, monocytes and macrophages in the medial preoptic area, as well as on endotheliocytes of the terminal vessels. Under pyrogenal effect activation of microglial cells and pericytes also takes place, and as a result of the rearrangements, occurring in the structure, they change into macrophages. This is an evidence of their active participation in the immune protection of the brain. According to the data from other investigations, all these activated cells produce peptide interleukin-1, one of the mediators of fever and stimulator of the immune system. Pyrogenal is stated to produce a stimulating effect on the astroglia and on some neurons of the medial preoptic area, that respond with cytoplasm increase and accumulation of numerous organelles. The reactive changes at fever in some neurons of the medial preoptic area can demonstrate that they belong to the thermosensitive pool. A conclusion is made, concerning a complex effect of pyrogenal, that results in a cooperative response of a number of cellular systems of the organism.

[Effect of synaptically active substances on the hyperthermic effect of prostaglandin E2 in rats]. / Vliianie sinapticheski aktivnykh veshchestv na gipertermicheskii effekt prostaglandina E2 u krys.

It was established in experiments on unanesthetized rats given intraventricular injections of drugs that hyperthermic effect of prostaglandin E2 (PGE2) was markedly weakened by administering clofelin while isoproterenol had no appreciable effect on PGE2 effects were not prevented by noradrenaline, 5-hydroxytryptamine, phenoxybenzamine, propranolol, deseril, nicotine, metamyzyl and IEM-506. Preliminary administration of oxotremorine and hemicholinium-3 averted PGE2 effect. The disorders of the thermo-regulation centers caused by excess PGE2 are likely to be counterbalanced by the central effect of some synaptically active drugs which affect in particular the function of cholinergic synapses and alpha-adrenoreceptors.

[Reduction of the hyperthermic effect of prostaglandin E2 by cholinomimetics, monoamines and calcium ions]. / Oslablenie gipertermicheskogo éffekta prostaglandina E2 kholinomimetikami monaminami i ionami kal'tsiia.

It was shown in experiments on unanesthetized rats with prostaglandin E2 (PGE2) hyperthermia, not preventable by aspirin that intraventricular (into the lateral ventricle) injections of arecoline, noradrenaline, 5-hydroxytryptamine (5-HT), histamine, and calcium ions and intraperitoneal eserine injection were capable of decreasing body temperature. PGE2 hyperthermia was not prevented by aspirin, but it was reduced by eserine. After the administration of arecoline and nicotine into the third ventricle of unanesthetized rabbits with PGE2 hyperthermia body temperature decreased as well. The effect of arecoline and 5-HT was reproducible in the same animals. The data are suggestive of the existence in the heat loss centre of mechanisms including cholinergic neurons whose activity was not completely suppressed by PGE2.