[Dynamics of daily rhythm changes of arterial blood pressure in hypopinealism].

The article presents the original data on the character of the changes in arterial blood pressure (ABP) in rabbit with hypopinealism induced by long 24-hour lighting. In experimental animals registered leveling the daily rhythm of ABP primarily because of increase this value in dark time (night, evening) and formation of arterial hypertension by 'non-dipper".

[Role of the change of daily rhythms of adrenaline and noradrenaline concentration in blood in the mechanism of accelerated aging in hypopinealizm induced by a long period of day and night lighting].

In young adult male rabbits circadian rhythms change of blood concentrations of adrenaline and noradrenaline in the dynamics of hypopinealism development induced by a long period (5 months) twenty-four-hour lighting of low intensity (30-40 lux) were studied. It was found that the light in the night leads to a significant increase in the levels of both catecholamines, which indicates on the activation of the sympathoadrenal system (SAS), just as it occurs in aging and stress (stress-age-syndrome by V.V. Frolkis). Daily features of SAS reactions to light stress were revealed. Based on these data it can be concluded that one of the reduction mechanisms of life expectancy at hypopinealizm is excessive and prolonged activation of SAS.

Intensity of in vitro incorporation of 3H-melatonin in the thyroid gland of rabbits with pineal gland hypofunction.

The structure and hormonal activity of the thyroid gland and its capacity to bind (3)H-melatonin were studied in young adult Chinchilla rabbits with pineal gland hypofunction induced by 2-month exposure to constant illumination. After 2 months of constant exposure to light, the experimental animals exhibited signs of the so-called "latent hypothyroidism" and more intense binding of (3)H-melatonin by the thyroid gland. This fact indicated intactness of its receptor system underlying the possibility of restoring activity of the thyroid gland under conditions of melatonin replacement therapy in hypothyroidism induced by chronic melatonin insufficiency.

[The morphological response of the pineal gland of old animals on course of melatonin injections].

On the old (18-20 months) male rats of Wistar population the influence of the 10 days evening melatonin injections in physiological rang doses on morphological state pineal gland, was studied. It has been shown, that the course of melatonin injections to old rats brings appearance of histological pattern of pineal gland activation: increasing of area of pinealocytes nuclear and density of nuclear and cytoplasm with stein by hallocyanine on total nucleic acid that means stimulation to material both indole, and peptide nature production. Using of melatonin in dose 0.05 mg/kg mass of the body is sparing for pinealocytes of the old rats and slows the apoptosis processes on background of polyploidization. Using of melatonin in dose 0,5 mg/kg mass of the body causes cell's overstrain and induces the forced apoptosis. It's possible to suppose that the geroprotective effect of the evening injections of melatonin is increased due to stimulation of the biosynthesis of neuropeptides in pineal gland.

[Long round-the-clock illumination as a factor of accelerated ageing of pineal gland].

On sexually matured male rabbits of Shinhilla breed kept in round-the-clock illumination within 5 months, dynamic of changes of structure of pineal gland was investigated. It was found the gradual, progressing in time loss of pinealocytes amount, arising due to their apoptosis, which points out hypolinealism development. Round-the-clock illumination should be considered as the factor promoting accelerated aging of pineal gland.

Circadian rhythms of in vitro incorporation of 3H-melatonin into organs of the hypothalamic-pituitary-thyroid system in rats.

Circadian rhythms of the intensity of 3H-melatonin absorption by organs of the hypothalamic-pituitary-thyroid system were studied in young mature male Wistar rats in summer. The hypothalamus, pituitary, and thyroid gland incorporated 3H-melatonin during the day and night hours, but the intensity of its incorporation in the pituitary and thyroid was high during daytime and low at night, while absorption of the hormone by the hypothalamus tended to be higher at night.

[Effect of long-term around the clock illumination on rabbit serum phospholipids].

This study was designed to investigate the effects of light on pineal gland function and phospholipids contents in the blood serum of rabbits. The level of melatonin in the blood serum was significantly reduced and endogenous rhythm of the melatonin secretion brok down under constant illumination conditions. Two-month treatment of rabbits with light led to a significant and short-term decrease of the phosphatidylethanolamine and phosphatidylinositol + phosphatidylserine levels in the serum. The contents of the other lipids under study (phosphatidylcholine, lysophosphatidylcholine and sphingomyelin) in blood increased later under 3-5 month-long constant illumination conditions. The results obtained demonstrate important role of pineal gland in the regulation of phospholipids metabolism.

Role of methionine in nocturnal melatonin peak in the pineal gland.

Methionine dose-dependently stimulated O-methylation of hydroxyindoles in the pineal gland and contributed to the nocturnal melatonin peak in adult male Wistar rats. Methionine is involved in the maintenance of diurnal rhythms by regulating biochemical transformations of indoles in pinealocytes. Our findings provide theoretical basis for new applications of methionine.

[Hemodynamics, electrophysiological parameters of the heart and differential therapy of attacks of atrial fibrillation in patients with subclinical thyroid dysfunction]. / Osobennosti gemodinamiki, élektrofiziologicheskikh pokazatelei serdtsa i differentsirovannaia terapiia paroksizmov fibrilliatsii predserdii u bol'nykh s subklinicheskoi disfunktsiei shchitovidnoi zhelezy.

Thirty patients with subclinical thyrotoxicosis and 32 with subclinical hypothyroidism with attacks of atrial fibrillation were investigated. At levels of thyroid-stimulating hormone below 0.1 or above 10.0 mIU/l average triiodothyronine and thyroxine levels in patients with subclinical thyrotoxicosis were 89.6 and 73.2%, respectively, higher than in patients with subclinical hypothyroidism. Some relationships were found between levels of thyroid hormones and hemodynamic and electrophysiological parameters of the heart. Differential therapy of attacks of atrial fibrillation was effective in 80 and 62.5% of patients with subclinical thyrotoxicosis or hypothyroidism, respectively.

Morphofunctional changes in the pineal gland during dynamic adaptation to hypothermia.

The effects of stress induced by hypothermia (+4 degrees C for 3 h) on the pathways of serotonin metabolism in the pineal gland and on its structure were studied in adult male Wistar rats. These experiments showed that the melatonin-forming function of the epiphysis undergoes phasic changes during adaptation: there was a significant increase during the first 15 min, which was followed by gradual inhibition (to initial by 30 min) and then sharp suppression (at 3 h). Suppression of the functional activity of the pineal gland occurred because of exclusion of a proportion of pinealocytes from the process of active functioning.

[Thyroid hormones effects on hemodynamic and electrophysiological indices of heart performance and efficiency of antiarrhythmic drugs in paroxysms of cardiac fibrillation in patients with coronary heart disease]. / Vliianie tireoidnykh gormonov na gemodianmicheskie i élektrofiziologicheskie pokazateli raboty serdtsa i éffektivnost' antiaritmicheskikh sredstv pri paroksizmakh mertsatel'noi aritmii u bol'nykh ishemicheskoi bolezn'iu serdtsa.

The article provides the results of thyrotropic hormones (TH) influence on spontaneous paroxysms of cardiac fibrillation (CFP), central hemodynamics, electrophysiology (EP) of the heart and effectiveness of antiarrhythmic drugs (AAD) in patients with coronary heart disease (CHD). It is shown that in CFP patients TH should be evaluated in sinus rhythm and in arrhythmia. Fluctuations in TH contribute to CFP. EP and hemodynamic effects of TH manifest with shorter effective refractory period of the left atrium and atrioventricular junction, disturbed diastolic function of the left ventricle. TH affect efficiency of AAD in CFP patients with CHD.

Chronobiological aspects of melatonin-produced antioxidant effects in senescent rats.

Melatonin in low doses of (0.05 and 0.5 mg/kg) administered to senescent rats in winter and summer inhibited free radical oxidation and LPO. The antioxidant effect of melatonin increased with increasing the dose of the hormone. Changes in test parameters were more pronounced in winter, but the directionality of changes did not depend on the duration of the light period.

[Morphofunctional changes in the pineal gland during adaptation to hypothermia]. / Morfofunktsional'nye izmeneniia pineal'noi zhelezy v dinamike adaptatsii k gipotermii.

The influence of hypothermal stress (+4 degrees during 3 h) on the ways of serotonin metabolism in pineal gland and its structure has been studied in dynamics on adult male Wistar rats. It has been revealed that melatonin-producing epiphyseal function suffers from phase changes in dynamics of adaptation--significant rising during 15 min. after beginning of the experiment, rehabilitation up to normal--in 30 min, and fast suppressing--in 3 hrs. Suppressing of the functional pineal activity is not due to switched serotonin metabolism with melatonin and new indoles release, but to a partial pinealocytes breaking from their active function.

[Biochemical bases for the antiseizure role of the pineal gland]. / Biokhimicheskie osnovy protivosudorozhnoi roli pineal'noi zhelezy.

Metabolism of serotonin was studied in pineal gland of Wistar rats with low and high rate of audio excitability as well as in the Krushinsky-Molodkina rat population genetically predisposed to audio-dependent convulsions. Intensive turnover of serotonin via N-acetyl serotonin into melatonin was found in pineal gland of rats insensitive to sensory stimulus, whereas the rate of this response was decreased in the gland tissue of animals sensitive to audio effects as well as inhibition of serotonin turnover into melatonin was noticed in pineal gland of rats predisposed genetically to audio-dependent convulsions.

[Age-related characteristics of the effects of epithalamin on serotonin metabolism in the pineal gland of rats]. / Vozrastnye osobennosti vliianiia épitalamina na metabolizm serotonina v shishkovidnoi zheleze u krys.

The biosynthesis of serotonin into melatonin was decreased in old (18-20-month) in comparison to young (4-5-month) male Wistar rats. 5-day morning injections to young and old rats with polypeptide pineal preparation (epithalamin) in a dose of 2.5 mg/kg of body weight induced the increase in the night peak of serotonin, N-acetylserotonin and melatonin in young and melatonin alone in old rats and did not influence 5-methoxytryptamine, 5-oxy- and 5-methoxyindoleacetic acids level. These data support suggestion of ultrashort loop between pineal peptides and indoles and that epithalamin increases the metabolism of serotonin into melatonin.

[The effect of long-term 24-hour illumination on serotonin metabolism in the rat epiphysis]. / Vliianie dlitel'nogo kruglosutochnogo osveshcheniia na metabolizm serotonina v épifize krys.

Continuous illumination of pubertal rats during their 1st month of life induced metabolism of serotonin in the pineal gland. This seems to be the basis of the mechanism by means of which the pineal gland interferes in the processes of biological rhythms photoregulation.

[Effects of excess and deficiency of thyroid hormones in the body upon blood melatonin in pubertal male rats]. / Vliianie izbytka i nedostatka tireoidnykh gormonov v organizme na kontsentratsiiu melatonina v krovi u polovozrelykh krys-samtsov.

Experiments have been carried out on Wistar line pubertal male rats in Winter. Radioimmunological method showed, that in intact animals the night peak of melatonin in blood was 994,36 +/- 195,99 pM/l, following ten-days intramuscular thyroxin injection (100 mg/100 g body mass)--2560,52 +/- 322,04 pM/1 and 20 days after, following bilateral thyroidectomy--117,13 +/- 16,35 pM/l, that totals 257,5% and 11,8%, respectively. Thus, the night peak of melatonin depends upon thyroid hormones concentration in blood.

[Epiphyseal-thyroid interrelations: effect of calcitonin on indole metabolism in health and in the presence of an excess of thyroid hormones]. / Epifizarno-tireoidnye vzaimootnoshenie: vliianie kal'tsitonina na metabolizm indolov v norme i na fone izbytka tireoidnykh gormonov.

A new regularity was established in a study of epiphyseal thyroid interrelationships: the opposite effect of the thyroid hormones (thyroxin and calcitonin) on the formation of methoxyindoles (melatonin, 5-methoxytryptamine) in the epiphysis. Thyroxin was shown to stimulate and calcitonin to inhibit O-methylation of serotonin in the pineal gland, and combined administration of both hormones levelled their action on one another. The inhibitory effect of calcitonin was more marked if a high basal level of melatonin was stimulated by preliminary administration of thyroxin. The authors assume that such a double control of the thyroid is "protective" for the epiphysis, preventing rapid depletion of reserves in case of excessive saturation of the body with thyroid hormones and maintaining its function in case of a sharp rise of the blood level of calcitonin.

[The biochemical aspects of pineal gland functioning in the rat in ontogeny]. / Nekotorye biokhimicheskie aspekty funktsionirovaniia pineal'noi zhelezy krysy v ontogeneze.

We have studied metabolic pathways of serotonin in epiphysis of Wistar male rats at the age of 1; 1,5; 2; 3; 6; 12; 24 and 36 months. Epiphysis retains its functional activity throughout the life, however, serotonin metabolism in epiphysis undergoes marked changes. The main regulatory principle is the switch of serotonin metabolic pathways in the pineal gland. Most distinct changes between hydroxy- and methoxyindols in epiphysis have been observed during the periods of age-associated hormonal rearrangements like sexual maturation or involution of the gonad function at the old age.