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Biomedical subjects

N E Ordian

Publications and source records attributed to N E Ordian.

At least 19 recordsLinked to original sources
PubMed2006

[Transcranial electrical stimulation activates the reparative regeneration and insulin-producing function of beta-cells in alloxan-induced diabetic rats].

In alloxan-induced diabetic rats, it was demonstrated that transcranial electrical stimulation of the brain endorphinergic structures activated the reparative regeneration of the damaged beta-cells of the Langerhans pancreatic islets. This was estimated on the histological sections of pancreas with hematoxylin-eosin staining. Several small newborn islets were found to originate from pancreatic progenitor cells. After transcranial electrical stimulation of insulin granules, beta-cells (Gomori's staining) were observed as an indication of the restoration of the insulin production. Correspondingly the increase of the blood insulin level was estimated by immune-enzyme method. The dynamics of the plasma insulin increase had a significant negative correlation with decrease of the blood glucose level. The glucose-lowering action of the transcranial electrical stimulation in alloxan-induced diabetic rats seems to be based on stimulation of the regeneration of damaged beta-cells with the restoration of their insulin production.

Alloxan↗
PubMed2005

[Behavioral activity and stress reaction of the pituitary-adrenocortical axis in rat with prenatal inhibition of testosterone metabolism].

The effects of maternal administration of the aromatase inhibitor, 1,4,6-androstatrien-3,17-dione (ATD), during the last week of gestation on stress reaction of the hypothalamic-pituitary-adrenal axis (HPA) and behavior in a novel environment (open field) and the anxiety level in the elevated plusmaze, were studied in male and female adult offspring. The results showed that parental inhibition of brain testosterone metabolism decreases the basic level of corticosterone in male rats and prolongs hormonal stress reaction of the HPA axis in both sexes. Prenatally treated rats demonstrated significant elevation of the anxiety level and emotionality. There was no sexual dimorphism in behavioral response to a novel environment such as locomotor activity, the time of immobilization, the total duration of grooming reaction, and the anxiety level, between control male and treated female rats. These data suggest a prenatal inhibition of the brain testosterone metabolism after the stress reaction of HPA axis and formation of sexual dimorphism in the anxiety and behavioral response to a novel environment in adulthood.

Androstatrienes↗
PubMed2003

[Behavioral characteristics and stress reaction of the pituitary-adrenal system in prenatally stressed rats].

Mothers' stress was shown to considerably diminish the orienting-studying activity of male rats in the dioestrus stage, as well as enhancement of anxiety. In prenatally stressed male rats, on the contraty, the anxiety diminished while their behaviour in the open field tests remained practically unaltered. The prenatal stress affected the stressor response of the hypophysis-adrenal systems in both sexes. The data obtained suggest that the mothers' stress affects both behaviour and stressor response in male as well as female rats.

Animals↗
PubMed2002

[The anxiety level and synthesis of neurosteroids in the brain of prenatally stressed male rats].

Prenatal stresses significantly reduce the anxiety level and enhance motor activity in mature male rats. An enhancement of the 5 alpha-reductase activity occurs in the hypothalamus, hippocampus, and the brain frontal cortx. The data obtained suggest that behavioural changes in mature male rats due to prenatal stresses may be a consequence of an increased forming of active progesterone metabolities in the brain.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed2002

[Participation of the brain catecholamines in changes in activity of the rat hypophyseal-adrenal system induced by hydrocortisone administration during neonatal ontogenesis].

Administration of hydrocortisone or 6-hydroxydopamine (6-ONDA) to little rats from the 1st to the 5th day of life affected functional activity of the hypophyseal-adrenal system (HAS) of immature rats. In the morning hours, the rats developed a decrease in the basal and stressor levels of corticosterone in the blood, whereas administration of the 6-ONDA did not change the functional activity of the HAS in the morning. The data obtained suggest that disorders in the HAS regulation by the feedback mechanism resulting from neonatal administration of hydrocortisone may be associated with a drop in the noradrenaline level in the hypothalamus.

Adrenergic Agents↗
PubMed2001

[Changes in the neuroendocrine regulation of adaptive behavior in rats subjected to stress in the late prenatal ontogenesis].

Female rats were subjected from the 14th to 17th day of pregnancy to immobilisation under conditions of 1-hour daily bright illumination. On the 20th day, contents of testosterone and estradiol was decreased with no sex difference in their level in the pregnant female rats' blood and in the amniotic fluid. Sex differences were flattened in 1-month litter both in the androgen and oestrogen contents and in adaptive behaviour. In prenatally stressed males, motor activity was inhibited and anxiety was enhanced as compared with the control. At one and a half months of age, the consequences of the prenatal stress disappeared and then reappeared after sexual maturation but with an opposite trend. Adaptive behaviour of adult males was less flexible and revealed no age-dependent oscillations inherent in the control animals. Prenatal stress while preventing the maximal raise of sex steroids in the blood shifts sex differentiation of the adaptive behaviour toward demasculinization.

Adaptation, Psychological↗
PubMed2000

[Changes in the hormonal function of the hypophysis-adrenal system by administration of cortisol in 'fixed' phases of the postnatal ontogenesis in rats].

Administration of cortisol on the 13th, 15th, and 17th days of postnatal ontogenesis was shown to exert a long-lasting modifying effect upon the hypophysis-adrenal system's (HAS) stress reactivity in the rat litter. The effect involved a longer duration of hormonal response to immobilisation stress: a longer-lasting elevation of the corticosterone level in the blood plasma suggesting a diminished sensitivity of the HAS to feed-back signal. In hippocampus, frontal cortex and hypothalamus of the experimental rats, a decrease in receptor binding of labeled corticosterone was revealed.

Animals↗
PubMed1999

[Changes in secretion of sex steroid hormones during stress in rats with various brain excitability].

A stress procedure decreased the plasma progesterone faster in highly excitable rats than in the less excitable those. The decrease in gonadal and adrenal progesterone was still obvious in 24 hours in both groups of rats but more obvious in the former group in respect to the progesterone level. The data obtained may help to understand individual ability to respond to a stress in a different way depending on functional condition of the hypothalamo-pituitary-adrenal axis.

Adrenal Glands↗
PubMed1996

[The effect of controllable and uncontrollable stressor actions on dexamethasone receptor binding in the hypophysis and hippocampus of rats with different behavioral strategies].

Exposure to inescapable foot shocks (ISs) decreased the dexamethasone receptor binding in the KHA rat hippocampus. Both the ISs and escapable foot shocks (ESs) enhanced the binding in the pituitary of the KLA rats as well as their plasma corticosterone. The data obtained suggest that the brain corticosteroid binding depends on the coping style of the subject as well as on the stress controllability factor.

Animals↗
PubMed1995

[The evaluation of corticosteroid hormone receptor status in the brain structures of stressed and adrenalectomized rats].

The value of receptor capacity in respect to cytosol concentration was shown to vary, therefore two criteria are proposed for estimation of condition of the cytosol corticosteroid receptors: the density of the receptors in tissue and the range of intermediate (active) complex. The number of receptors in the hypophysis was shown to reduce after adrenalectomy whereas in the hypothalamus, hippocampus and striatum it increased. The range of intermediate complex was shown to change differently in different structures after stress.

Adrenal Glands↗
PubMed1995

[The characteristics of the corticosteroid receptors in the hormonal modification of the stress reactivity of rats].

After neonatal administration of hydrocortisone the rat litter preserve inhibition of function of the hypophyseal-adrenal system at the age under 2 months. During the inhibition period, the number of corticosteroid receptors was decreased in the hypothalamus and hippocampus and increased in the hypophysis. At the 3-month age, binding of corticosteroids in these structures is restored.

Adrenal Glands↗
PubMed1995

[Neuroendocrine mechanisms in the shaping of adaptive behavior].

Behavioral and neuroendocrine responses to stressfull factors action is genetically determinated programm of individual development and is formed in pre- and postnatal ontogenesis. This responses may be changed by stressors action or corticosteroid hormone injection during ontogenety "critical" period. Inhibition of some neuroendocrine or neuromediator system is fulfilled through mineralo- and glucocorticoid receptors and promote of behavioral modifications beginning.

Adaptation, Physiological↗
PubMedDate not supplied

[The modification in the level of sex steroids and anxiety as a result of maternal stress].

We studied the effects of a restraint of female rats in the last third of pregnancy (14-17 days) on the level of sex steroids and anxiety both in mothers and pups. The restraint significantly changed the open-field behavior and testosterone and estradiol blood levels in pregnant dams. In the offsprings, it eliminated sex differences in anxiety, locomotor activity, and "freezing" duration as well as in blood content of sex steroids. Involvement of sex hormones in the early ontogenetic (prenatal) development of behavior is discussed.

Adaptation, Physiological↗