[Effect of space flight factors simulated in ground-based experiments on the behavior, discriminant learning, and exchange of monoamines in different brain structures of rats]

Experimental treatment (long-term fractionated γ-irradiation, antiorthostatic hypodynamia, and the combination of these factors) simulating the effect of space flight in ground-based experiments rapidly restored the motor and orienting-investigative activity of animals (rats) in "open-field" tests. The study of the dynamics of discriminant learning of rats of experimental groups did not show significant differences from the control animals. It was found that the minor effect of these factors on the cognitive performance of animals correlated with slight changes in the concentration ofmonoamines in the brain structures responsible for the cognitive, emotional, and motivational functions.

[Changes in gastric electric activity and serum catecholamine level under the influence of electromagnetic microwaves (experimental studies)]

Chronic experiments on 17 dogs revealed that ultrahigh-frequency electromagnetic waves applied on epigastric area and head induce a double-phase response: depressed electric activity of gaster and increased total catecholamines level during exposure, but higher gastric activity and lower levels of epinephrine and norepinephrine in 24 hours after each of 10 procedures and during 7 days after 10 procedures. Double-phase changes in electric activity of gaster could be explained by double-phase fluctuations of humoral division in chromaffin system.

The influence of amitriptyline and flunarizine on catecholamine response to light in patients with migraine

The effect of amitriptyline on catecholamine (CA) response to light of 20 migrainous patients was studied. The drug was given orally, 36 mg daily (12 mg x 3), for ten days. Before therapy, the migraineurs responded to light by an increase in epinephrine (E) excretion and not by the rise in norepinephrine (NE) excretion, noticed in controls. The NE excretion of migrainous subjects underwent very often a depression after photostimulation. Amitriptyline therapy prevented the post-photic rise in E excretion of migraineurs, without influencing significantly the variation in NE excretion produced in them by light. In other 8 migrainous subjects the effect of flunarizine, a selective calcium channel blocker, on CA response to light was tested. The dosage was of 5 mg daily, for ten days. Flunarizine had similar effects to those displayed by amitriptyline; the drug prevented the rise in E excretion produced by light without normalizing the NE response to light of migrainous subjects. The results suggest that the efficiency of these two drugs in migraine prophylaxis is connected with the ability of these substances to block the E discharge produced in migraineurs by light or by other stimuli. The interpretation is all the more likely as propranolol, another drug applied in migraine prophylaxis also blocks the post-photic E discharge of migraineurs.

[The functional status of the hypophyseal-adrenal cortical adaptation system in children in Byelarus living under the action of low doses of radiation after the accident at the Chernobyl Atomic Electric Power Station]

The analysis of the status of sympatho-adrenal and hypophysis-adrenal medulla systems of adaptation in children living in territories contaminated by radionuclides was carried out. A decrease in the catecholamine level in children's urine and hyperactivity of the hormonal response of adrenal medulla to endogenous ACTH indicated the reduced ability of adaptation and decreased resistance of children's organisms to stress factors of the environment.

[Changes in mast cells after their exposure to constant electromagnetic field]

By means of luminescent histochemistry effect of a constant magnetic field with induction 60 mTl (exposition for 2, 6, 36 h and 7 days) has been studied in order to reveal contents of catecholamines in mesenteric mast cells and in the intestinal mesentery cells in 50 white Wistar rats. In 2-6 h specific luminescence of the mast cells increases, however, at prolongation of the exposure up to 30 h metabolism of catecholamines in the mast cells is inhibited noticeably++ (luminescence disappears). In 8 days amount of the mast cells and specific luminescence of catecholamines decrease. The essential shifts revealed in the system of the mast cells of the mammalian should be taken into consideration in the magnetic-therapeutic practice. Close spatial relations between the mast cells and the mesenteric adrenergic terminals have been elucidated, demonstrating their morphofunctional interconnection.

[The effect on an impulse electromagnetic field on the bioamine allowance of the spinal ganglion in rats under whole-body exposure]

In experiments with albino male rats subjected to whole-body pulse electromagnetic irradiation of 100 mTl magnetic induction, the luminescent histochemical methods and the subsequent microspectrofluorometry were used to determine the content of biogenic amines (catecholamines, serotonin, and histamine) in spinal ganglia neurons. Significant changes were revealed not only in the content of all studied bioamines but in the histamine/serotonin ratio as well.

[The effect of prolonged exposure to gamma rays and hormonal stimulation with serum gonadotropin on the levels of catecholamines in the hypothalamus, epiphysis and adrenal glands in sheep]

The effect of the exposure of the whole body to continuous radiation and of the administration of serum gonadotropin (SG) was studied as exerted on the concentration of catecholamines (epinephrine and norepinephrine) in the hypothalamus, epiphysis and adrenal glands of ewes during the anoestric period with synchronized oestrus. The first group (young barren ewes) and second group (older ewes) were exposed to continuous radiation of 60Co for five days. The radiation was provided at the rate of 0.020 Gy per hour. After the termination of irradiation the ewes were subjected to hormonal stimulation by fractionated administration of 1500 I. U. SG. The third and fourth experimental groups of ewes were stimulated with 1500 I. U. SG without irradiation. Catecholamines were separated from the tissue supernatants by the adsorption chromatographic method and the catecholamine contents in the eluates were determined spectrofluorometrically. Protracted exposure to gamma radiation and hormonal stimulation with SG reduces the concentration of norepinephrine in the whole hypothalamus of the sheep. A statistically significant decrease (P less than 0.001) was recorded in the medial and caudal hypothalamus of the adult ewes and in the rostral and caudal hypothalamus regions of the young ewes. A decrease of norepinephrine concentration, statistically significant in the caudal (P less than 0.01) and medial hypothalamus, was recorded in the group of adult ewes after hormonal stimulation with SG without irradiation. The experimental group of young ewes responds to hormonal stimulation by a greater reduction of norepinephrine contents, as compared with combined exposure to radiation and hormonal stimulation. It is assumed that the decrease in catecholamine concentration after hormonal stimulation with SG is associated with the increase in the content of oestrogens, which act on the adrenergic receptors of the hypothalamus.

[Levels of catecholamines in the hypothalamus, hypophysis and in the adrenal in sheep after whole-body exposure to gamma rays]

The changes were studied in the levels of catecholamines and L-DOPA in the control system of reproduction cycle (hypothalamus, hypophysis) and in adrenal glands of sheep after all-body irradiation with 60Co at the total dose of 6.7 Gy for seven days. The power input per hour of irradiation source was 0.039 Gy. The catecholamines (noradrenaline, dopamine and adrenaline) and L-DOPA were determined, after having been isolated from the tissues, by the method of spectral fluorimetry. After all-body exposition to gamma-radiation noradrenaline dropped in hypothalamus in comparison with the control group of sheep, most significantly in the rostral (by 74.2%) and caudal part (by 40%). A similar drop like in the case of noradrenaline was also observed in dopamine, the concentrations of which decreased in rostral hypothalamus by 72%, in medial hypothalamus by 94% and in caudal hypothalamus by 60%. Adrenaline shows a drop in hypothalamus, most significant in caudal region (by 62%). In relation with that the level of a precursor for the synthesis of catecholamines and L-DOPA has been changed which achieved, in the studied regions of hypothalamus in sheep, significantly lower levels than were determined in the control group of sheep. As regards the hypophysis, after irradiation no significant changes in the levels of noradrenaline and adrenaline were recorded, however, dopamine and L-DOPA dropped significantly (P less than 0.01). The exposition to gamma-radiation also causes a decrease in the concentrations of catecholamines and L-DOPA in the adrenal glands of sheep, most significant in noradrenaline (by 61%).(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of acetylcholine and histamine on electrolyte and catecholamine content of vessel walls exposed to x-rays and cystamine]

Experiments on adult rats have shown that a single rectal x-ray irradiation is accompanied by a decrease in the content of adrenaline, noradrenaline and potassium and by a increase in sodium and calcium concentration in vascular tissue. The degree of these shifts depends on the time elapsed after exposure to x-rays. X-Ray injury produces specific changes in the biochemical response of the vascular wall to different doses of acetylcholine and histamine during varying times of x-ray-induced pathology. Pretreatment (before irradiation) with radioprotectors (cistamine) lowers the damaging effect of radiation and promotes the normalization of the vascular tissue response to the administration of mediator agents.