[Neuroendocrine factors in pathogenesis of motion sickness and the protective effect of drugs].

The paper presents a generalization of many-year complex investigations performed at various departments of the Institute of Medico-Biological Problems (Moscow) and various laboratories and institutes of the Ministry of Public Health and the Russian Academy of Medical Sciences, devoted to the pathogenesis of motion disease (sea sickness, vestibulo vegetative syndrome, various forms of kinetosis). The main attention is given to interpretation of the mechanisms of therapeutic and prophylactic action of drugs used for the treatment of such disorders. In particular, the role of a hormonal component of the system of regulation of physiological functions is considered as manifested in the models of the vestibulovegetative syndrome and in the pharmacotherapy of the motion disease.

Endocrine responses to space flights.

Simultaneously with human space flights several series of observations were performed by using experimental animals--mainly rats--exposed to space flights on board of special satellites BION-COSMOS or in Shuttle Transportation Systems (STS). The aims of these experiments were to study in more details: the mechanisms of the changes in bones and skeletal muscle, the alterations of the function of immune system, the radiation effects on organism, the mechanism of the changes of endocrine functions, the evaluation of the role of hormones in alteration of metabolic processes in organism. The advantages of these animal experiments were the possibilities to analyze not only the plasma samples, but it was possible to obtain samples of organs or tissues: for morphological and biochemical analysis for studies of the changes in enzyme activities and in gene expressions, for measurement of metabolic processes and for investigation of the hormone production in endocrine glands and estimation of the response of tissues to hormones.

Changes of hormones regulating electrolyte metabolism after space flight and hypokinesia.

The changes of hormones in plasma involved in the body fluid regulation were studied in human subjects during and after space flights in relation to redistribution of body fluids in the state of weightlessness. Since hypokinesia was used as a model for simulation of some effects of the stay in microgravity the plasma hormone levels in rats exposed to hypokinesia were also investigated. Plasma aldosterone values showed great individual variations during the first inflight days, the increased levels were observed with prolongation of space flights.

Effect of space flights on plasma hormone levels in man and in experimental animal.

An important increase of plasma hormone levels like insulin, TSH and aldosterone was observed in human subjects after space flights, however in the changes of plasma content of ACTH, cortisol, adrenaline and noradrenaline the individual variations were observed in relation to number and duration of space flight. For evaluation of the effects of these changes in plasma hormone levels on metabolic processes also the experiments with small animals subjected to space flights on a board of biosatellite of Cosmos series were running. An elevation of plasma levels of corticosterone, adrenaline, noradrenaline and insulin was found in rats after the space flights of duration from 7 to 20 days.

[Effect of electromagnetic SHF-radiation on the morphofunctional status of early mouse embryos].

A differential effect of 915 MHz microwave radiation with 500 Hz amplitude modulation of 1 ms pulses on the morphofunctional state of mouse 8-cell embryos has been shown. Then development is not disturbed by irradiation for 15 to 20 min. This effect is suggested to correlate with some changes in the properties of cell membranes as a result of possible local increases of temperature.

[Characteristics of the acidic extract from the epiphysis and its fractions].

Acid extract of bovine epiphyses was separated by means of gel filtration on Sephadex G-50 into two fractions: high and low molecular preparations. Estimation of biological activity of the acid extract and its polypeptide fractions, which was carried out using the procedure of antigonadotropic effect on preadolescent rat females, showed that the antigonadotropic effect was distinctly higher in the preparation free of high molecular substances.

[Change in carbohydrate metabolism, secretion of insulin and glucagon in normoglycemic rats during administration of various doses of nicotinamide].

Development of hypoglycemia, a slight decrease in concentration of glucagon in blood as well as increase in activity of malate-and glucose-6-phosphate dehydrogenases in liver cytosol were detected in rats injected subcutaneously with nicotinamide at a dose of 31.25 mg/kg 6 hrs before decapitation. Increase of the single dose up to 125 mg/kg caused hypoglycemia, distinct increase in concentration of insulin and glucagon in blood plasma simultaneously with a pronounced inhibition of the enzymatic activity in liver tissue.

[Possible mechanism of specific action of pulsed UHF-fields].

Experimental data were obtained for conditions of stimulation of mechanical vibrations in the liquid models of microwave fields. Possible role of different elastic waves modes in the formation of specific effects in pulsed HF-fields is discussed. Mathematical estimation suggests that excited shearing waves may have biological action.

[Frequency range of the auditory effect of UHF].

Zero beats of radiosound with an acoustic signal from an electrodynamic emitter in the frequency range up to 8 kHz were recorded in a natural experiment, which were not obtained earlier. It has been shown that the zero beats between the acoustic tonal signal and the first harmonics of the impulse succession of UHF are recorded in the points which correspond to low values on the threshold curve of UHF auditory effect.

[Neuropharmacology of the autonomic vestibular syndrome].

It was found during studies on man and experiments on animals that various neuromediator systems of the organism (M-cholinergic, H1-histaminergic, dopaminergic, and opioidergic) are involved in the genesis of VVS. In addition, animal experiments showed that of great importance in the process are different regulatory peptides, in particular, substance P and beta-endorphin. The findings indicate that some neuropeptides may be used in the future in man for VVS prevention.

[Hormonal response of the bodies of cosmonauts after completion of brief space flights].

After short-term (7-day) space flights the following parameters were measured in blood of cosmonauts: cortisol, ACTH, aldosterone, thyrotropic hormone, thyroxine, triiodothyronine, somatotropic hormone, insulin, testosterone, cyclic nucleotides, prostaglandins, activities of the kallikrein-kinin, fibrinolytic and coagulatory systems, and plasma renin activity; in addition, renal excretion of aldosterone and total 17-oxycorticosteroids was determined. It was demonstrated that after the short-term flights the acute period of adaptation was accompanied by a moderate activation of the renin-angiotensin-aldosterone system, adrenal glucocorticoid function, pancreatic insular apparatus, kallikrein-kinin system as well as increased cyclic AMP which is suggestive of a moderately expressed stress-reaction.

[Hormonal metabolic status of the human body under the conditions of the Far North].

The concentrations of hormones (ACTH, cortisol, aldosterone, thyrotrophin, thyroxine, triiodothyronine, growth hormone, insulin, prolactin and testosterone), electrolytes (Na and K) as well as glucose and triglycerides were measured in 10 athletes who made a 380 km ski expedition in the Far North at ambient temperatures of -32 to -34 degrees C. Human adaptation to the geographic and climatic conditions of high latitudes was accompanied by noticeable changes in the incretory function of the adenopituitary, thyroid gland, adrenals and gonads. The data obtained indicate that a ski trip in the Far North produces a distinct stress with physical and cold components being predominant.

[Study of the characteristics of the effect of radio-sound using spherical models].

Experimental data are presented on sound wave excitement in liquid sphere models by pulse HF-fields and interpreted in relation to microwave auditory effects.

[Effect of long-term space flight on polyamine levels in the rat brain].

The concentration of polyamines, i.e. putrescine, spermidine and spermine, was measured in different brain compartments of rats flown for 18.

[Effect of pulse electromagnetic radiation on erythrocyte ghosts].

The pulse microwave radiation has been shown to increase the fluorescence intensity of 2-toluidinonaphthanene-6-sulfonate (2,6-TNS) and 1-anilinonaphthalene-8-sulfonate (1,8-ANS) built-in membranes of erythrocyte ghosts. In experiments with 2,6-TNS a frequency dependence of the effect of microwave radiation with maximum within the frequency range of 55-65 Hz has been found. It is suggested that the changes registered with fluorescent probes are induced by mechanical oscillations generated by the pulse microwave radiation.

[A physical model of acoustic effects of ultrahigh frequency fields on biological systems].

A physical model of radiosound based on the stimulation of mechanical oscillations in liquid media at adsorption of SHF impulse energy is presented. It is shown that a limited liquid volume can be considered as an acoustic resonator with self oscillation frequency. At definite relationships between the succession frequency and impulse duration interference takes place.

Endocrine response to acute changes of brain blood flow due to lower body negative pressure in man.

The decrease of brain flow due to lower body negative pressure (LBNP) was used to study the role of cerebral glucopenia in the activation of anterior pituitary function in 10 young healthy men. During LBNP with a maximum negative pressure of--50 mm Hg the changes in heart rate, blood pressure cerebral blood flow (with the aid of rheoencephalography) and electrocardiogram were recorded and the levels of hGH, ACTH, hPRL, insulin and cortisol were measured with the aid of radioimmunoassay. During the first investigation an infusion of 20% glucose (1 g per min for first 30 min and 0.