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Biomedical subjects

L Pascalov-Stoenescu

Publications and source records attributed to L Pascalov-Stoenescu.

12 recordsLinked to original sources
PubMed1975

Avoidance behaviour peculiarities induced by chronic treatment with L-DOPA in the neonatal period.

The aim of the research was to observe the effects of chronic treatment with L-DOPA in the neonatal period on reactivity in avoidance situations, the sympatheticoadrenal system being known to be constantly involved in the response to stress. At 3 weeks from birth the experimental group (52 chronically L-DOPA injected animals) was tested for the unconditioned avoidance behaviour (light-avoidance) limits, the capacity for learning and retaining a noxious significance in comparison to two control groups (53 animals injected with distilled water and 53 free of any such stress). The animals injected with L-DOPA since birth were significantly less than controls able to recall the noxioux significance they had trained on a single session and they extinguished eariler than controls did the conditioned passive avoidance response. The results are discussed from the point of view of the neurohormonal influence involved in setting up the specific avoidance phenotype.

Animals↗
PubMed1975

Heat adaptation patterns in infant rats during the first postnatal period.

In 129 infant rats divided into two groups housed to a constant ambient temperature of 21 degrees C, dynamics of body temperature and hypothermic reaction were studied. Beginning with day 1, the experimental group (66 animals), was exposed 15 min. daily for four weeks to an ambient temperature of +40 degrees C. Rectal temperature, temperature of hair-covered skin areas and tail temperature were monitored in either group. A statistically significant difference, which increased with age, between rectal and skin temperature, was found in experimental 3-week-old rats, while in control animals only in 45-day-old ones. Moreover, rectal and skin temperatures in the experimental group were significantly higher than in control group. The body-temperature difference between the two groups disappeared 17 days after cessation of exposure to heat. The hypothermic reaction induced by an weekly 2-min exposure to an ambient temperature of -1 degrees C, was significantly more important and extensive, in the experimental group than in the control one, during the first week of life only. The changes observed suggested a retarded development of the pituitary-corticoadrenal axis.

Acclimatization↗
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

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↗