Biomedical subjects

N Sterescu

Publications and source records attributed to N Sterescu.

40 records · Page 3Linked to original sources

PubMedDate not supplied

Enhanced acquisition and retention of passive avoidance behaviour in adult rats given a single transuterine ACTH injection while fetuses.

The long-term effects of a single ACTH injection administered to fetuses by transuterine way, on the ability to learn and retain a noxious significance were studied. The investigation was carried out on 115 adult rats of either sex. During the experiment the authors examined the range of inborn avoidance behaviour (light avoidance), as well as the ability to develop and retain a passive avoidance response. The ACTH-treated group did not present a significant difference of light avoidance behaviour as compared to controls, showing nevertheless a significantly higher learned passive avoidance and a delayed extinction of the noxious significance. The role of pituitary-adrenal hormones in the mechanism of avoidance behaviour during ontogenetic development is discussed.

Adrenocorticotropic Hormone↗

PubMedDate not supplied

The influence of cold or heat adaptation on some biochemical neuroendocrine parameters in infant rats.

The investigations were carried out on 192 Wistar newborn rats of either sex, chronically exposed to cold or heat. 32P-incorporation into cerebral phospholipids, phosphoproteins and nucleic acids (RNA and DNA) as well as 32P-uptake by hypothalamus, pituitary and adrenals were studied. The results showed that both chronic exposure to cold and heat enhance 3-P-incorporation into cerebral phospholipids, phosphoproteins and nucleic acids, the exposure to cold inducing nevertheless more important modifications. 32P-uptake by hypothalamo-pituitary-adrenal axis is also stimulated, this stimulation being higher in 14-day-old rats exposed to cold. The authors discuss the importance of the nature of stress, of the animal age and its level of CNS maturation in the appearance of all these modifications.

Age Factors↗

PubMedDate not supplied

Influence of early training to cold environment on some neuroendocrine patterns in adult rats.

Experiments carried out on Wistar rats of either sex: controls; early trained to cold (day 1--30) and handled newborn rats, killed on day 105 show that cold exposure during neonatal period induces long-lasting changes, which persist during the adult life. The most important changes concern CNS metabolism (modifications of 32P-incorporation into cerebral phospholipids, phosphoproteins and nucleic acids) and thyroid function. The authors discuss the mechanisms of these changes and their biological significance.

Age Factors↗

PubMedDate not supplied

Effects of training to heat and cold in the neonatal period on the body temperature response of adult rats.

Forty infant albino rats were divided into four groups. Group I was exposed 15 minutes daily for one month to a dry ambient temperature of +40 degrees C +/- 1 degree C and group II was exposed to 10 - 20 minutes daily to an ambient temperature of - 10 degrees C +/- 2 degrees C. Groups III and IV served as controls. When they had grown adult the animals of the experimental groups were exposed once to the temperature to which they had been trained. Basal temperature was measured and the temperature curve was recorded for 30 - 60 minutes after removing the animals from the hot or cold environment. Values were compared with those found in the control groups. The statistically processed results show that daily exposure to heat and cold does not influence the basal temperature of adult animals but impairs functional tests and resistance to limit temperature exposure. Thus, compared with controls, animals trained to cold developed a significantly lower hypothermia, whereas the animals trained to heat responded by a temperature rise equalling in height and duration that of controls when they were exposed to +40 degrees C, but displayed a significantly poorer resistance to lethal hyperthermic shock. The paper ends with a discussion of the mechanisms involved in these late effects, which are probably due to the impaired maturation of the pituitary-adrenal system in the neonatal period.

Age Factors↗