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N I Perassi

Publications and source records attributed to N I Perassi.

At least 19 recordsLinked to original sources
PubMed2002

Effects of maternal deprivation on adrenal and behavioural responses in rats with anterodorsal thalami nuclei lesions.

There is evidence that repeated maternal isolation of neonatal rats may influence both emotional behavior and Hypothalamic-Pituitary Adrenal (HPA) activity. On the other hand the Anterodorsal Thalami Nuclei (ADTN) exerts an inhibitory influence on the hypophyso-adrenal system under basal and stressful conditions. In the present work we investigated whether neonatal maternal deprivation produces long term effects on the ADTN regulation of behavioral patterns (open field test) and on HPA axis activity. Specifically, we sought to determine whether adult female rats with ADTN lesions, previously isolated for 4.5 hours daily during the first 3 weeks of life, react in endocrinologically and behaviourally distinct manner as compared to controls. The examined groups were: non maternally deprived (NMD)/sham lesioned, NMD/lesioned, maternally deprived (MD)/sham lesioned, MD/lesioned with and without the open field test. At 3 months MD/sham lesioned animals showed a marked decrease in ambulation (P < 0.01), and with ADTN lesion, the rearing values were lower (P < 0.01) and grooming higher (P < 0.05) than NMD. This last data would indicate a high emotional index. Regarding the activity of the HPA axis, maternal deprivation induced a significant decrease in plasma ACTH concentration both in sham and lesioned animals (P < 0.001), and plasma Corticosterone (C) increased in sham animals (P < 0.001). This data would indicate a higher sensitivity of the adrenal glands. After the open field test ACTH and C were different between deprived and non-deprived animals depending on the ADTN lesion. Taking into consideration the increase of ACTH levels in sham lesioned MD animals exposed to the test, we could conclude that this new situation was a stressful situation. Finally in the present work, it was very difficult to relate the behavioral parameters with the endocrine data. It is known that depending on the context, corticosteroids may produce opposite effects on emotional behavior via different receptors in the brain.In summary, neonatal maternal deprivation induced alterations of behavioral patterns and affected the ADTN inhibitory influence on ACTH and C secretion.

Adrenal Glands↗
PubMed2001

Periodic maternal deprivation and lesion of anterodorsal thalami nuclei induce alteration on hypophyso adrenal system activity in adult rats.

The hypothalamic-pituitary-adrenal (HPA) axis is normally regulated by extrahypothalamic limbic structures, among these, the anterodorsal thalami nuclei (ADTN), which exert an inhibitory influence on HPA, in basal and acute stress conditions in rats. In the present work we have investigated whether neonatal maternal deprivation (MD) produces long-term changes in the ADTN regulation of HPA activity. Maternal deprivation, in female rats, for 4.5 hs daily, during the first 3 weeks of life, produced at 3 months old, a significant decrease in plasma ACTH concentration (p<0.001) and an increase in plasma corticosterone (C) (p<0.001), compared to control non-deprived rats (NMD). Also MD showed higher plasma epinephrine (E) and norepinephrine (NE) levels than NMD rats. The increase of NE (66.6% p<0.001) was higher than that observed in E (19%). After 30 days of ADTN lesion, plasma ACTH values were higher than in sham lesioned rats, in both NMD and MD animals. ACTH response was greater in MD rats. Plasma C, in NMD, was higher, whereas in MD lesioned animals, it was significantly lower than in sham lesioned. In MD rats, lesion produced a significant increase in plasma E and NE (p<0.001), and again, NE increase was higher than E increase. The more accentuated increase of NE than E, suggests sympathetic nervous system hyperactivity. In summary, neonatal maternal deprivation induces long-term alterations on HPA axis sensitivity and medullo adrenal secretion; enhanced sympathetic nervous system activity and, therefore affected the ADTN inhibitory influence on ACTH and adrenal glands secretion.

Adrenocorticotropic Hormone↗
PubMed1998

Involvement of the anterodorsal thalami nuclei on the hypophysoadrenal response to chronic stress in rats.

Anterodorsal thalami nuclei (ADTN) exert an inhibitory influence on the hypophysoadrenal system (HAS) under basal and acute stress conditions; however, after chronic stress, the effect is different. The response to chronic immobilization stress (IMO) (forced immobilization for 15 min/day for 12 days) and variable chronic stress (V) (24-day exposure to different stressors per day) of plasma ACTH and corticosterone (C) in rats with anterodorsal thalami nuclei lesions was studied. In sham-lesioned rats, chronic immobilization stress and variable chronic stress induced a significant increase in plasma ACTH and C and a reduction of adrenal C content. After exposure of lesioned rats to chronic immobilization stress, there was a decrease of plasma ACTH compared to that in unstressed lesioned rats. In contrast, there was significant increase in ACTH levels after variable chronic stress, this increase being smaller than the variable increase elicited in sham-lesioned rats. In all stressed lesioned animals, plasma C remained unchanged. However, adrenal C content decreased significantly compared to that in unstressed lesioned rats. These findings demonstrate that anterodorsal thalami nuclei lesions attenuated the hypophysoadrenal system response to chronic stress. These data are in contrast to those obtained in previous studies under basal and acute stress conditions. The reason for this discrepancy is at present unknown, and its elucidation will require further studies.

Adaptation, Physiological↗
PubMed1997

Influence of anterodorsal thalami nuclei on ACTH release under basal and stressful conditions.

Experiments were carried out to evaluate the effect of anterodorsal thalami nuclei (ADTN) lesions on plasma ACTH and corticosterone (C), in unstressed and stressed rats. Thirty days after lesion, basal values of plasma ACTH, plasma and adrenal C were significantly higher than those in sham lesioned rats (p < 0.05: p < 0.05; p < 0.01, respectively). Chronic stress (forced immobilization, 15 min/day, during 12 days) in sham-operated animals produced a significat increase in ACTH (p < 0.05) and plasma C (p < 0.05), and a slight decrease in adrenal C, as compared to unstressed rats. In lesioned stressed rats, plasma ACTH was below that found in unstressed lesioned and in sham-lesioned stressed rats (p < 0.05). Variations of plasma C concentrations of stressed lesioned rats were not significant. The adrenal glands of stressed lesioned rats showed a significantly lower content of C than that in unstressed lesioned rats (p < 0.005). It is concluded that ADTN in rats may play a significant role in regulating the hipophyso-adrenal system.

Adrenal Glands↗
PubMed1994

Influence of anterodorsal thalamic nuclei on adrenal function in rats.

Experiments were carried out in order to elucidate a possible role of anterodorsal thalamic nuclei (ADTN) upon adrenal gland function in rats. Bilateral stimulation of ADTN produced a significant decrease in corticosterone concentration (C) in both plasma and adrenal tissue. After exposure to ether vapour, rats with bilateral lesion of ADTN showed that the increase in plasma C was markedly higher than that in the sham lesioned ones. Sham-lesioned stressed rats showed values of adrenal C higher than the values in sham unstressed rats. Whereas, ADTN-lesioned rats showed that adrenal C values were significantly lower than in the lesioned unstressed rats. The concentration of adrenal catecholamines, norepinephrine (NE) and epinephrine (E), in sham-lesioned rats was unaffected by ether stress. In stressed lesioned rats, adrenal glands contained 4 times as much NE and 2 times as much E as did the adrenal glands from lesioned unstressed rats. Our results suggest that the ADTN exert and inhibitory effect on adrenocortical function. They would involved in mediating the effect of stress in adrenal cortex and medulla in rats.

Adrenal Glands↗
PubMed1990

Interaction of some limbic structures which exert inhibitory effect on corticosterone secretion.

The interaction between limbic structures which exert inhibitory influence on corticosterone secretion was investigated in the rat. The following experiments were performed: 1) electrical stimulation at mammillary medial nucleus (MMN) in rats with lesioned anterodrosal thalami nucleus (ADTN) or intermediate tegmental area; 2) electrical stimulation at ADTN in rats with lesioned retrosplenial cortex (RC). Bilateral stimulation at MMN in ADTN or RC-lesioned rats produces an increase in plasma corticosterone concentration. In animals with lesioned RC, values of plasma corticosterone after stimulation at ADTN were higher than before stimulation. Taking into consideration that electrical stimulation of MMN or ADTN in intact rats produces a decrease in plasma corticosterone concentration, these studies demonstrate that MMN and ADTN exert inhibitory influence on corticoadrenal activity only when their projection areas remain intact.

Animals↗
PubMed1990

[Body weight and adrenal function in rats with "foster mothers" from the moment of birth].

In rats, the effect of the separation from their mothers on the corporal weight and on the levels of adrenal hormones, adrenal and plasmatic corticosterone and adrenal catecholamines was studied. The litters were grouped according to: a) maintained with their biological mothers, and b) maintained with their mothers interchanged immediately after birth (foster mother). All were lactating mother rats. In group b) the corporal weight was lower (p less than 0.001) than in group a) from the 14th to the 28th day of life, their weight increased thereafter. The levels of adrenal corticosterone were higher (p less than 0.01) in group b), but the plasmatic corticosterone levels were similar to that in group a). With respect to catecholamines, the noradrenaline values were higher in group b) (p less than 0.001), whereas the adrenaline levels were lower (p less than 0.01) than those in group a).

Adrenal Glands↗
PubMed1988

Plasma corticosterone responses to lesions and stimulations of the limbic thalami nuclei, medial mammillary nucleus and cingulate cortex.

The influence of extrahypothalamic limbic structures on adrenocortical activity was investigated in female adult rats. Bilateral lesions on the anteromedial thalami nucleus (AMTN), anteroventral thalami nucleus (AVTN) or the posterior cingulate cortex (PCC) all elicited a significant decrease on plasma corticosterone, while their electrochemical stimulation produced a significant increase with respect to animals with sham lesions or sham stimulation. In contrast, after lesions of the dorsomedial thalami nucleus (DMTN), medial mammillary nucleus (pars lateralis) (MMN) or retrosplenial cortex (RC), values of plasma corticosterone were significantly higher than those found in controls, whereas following their stimulation plasma corticosterone levels were lower than in controls. Bilateral lesions or stimulations of anterior cingulate cortex had no significant effect upon corticosterone secretion. These findings may be interpreted as indicative of the existence of excitatory (AMTN, AVTN, and PCC) and inhibitory (DMTN, MMN and RC) central nervous structures for the control of corticoadrenal secretion besides those already known.

Animals↗
PubMed1980

Circulating thyroxine levels in institutionalized children.

The circulating levels of total thyroxine (T4) and normalized thyroxine (T4N) were studied in 41 institutionalized children (IC) and in 22 control children (CC), from two to six years old. No difference were observed in the values of T4 between the two groups but in IC, T4N levels are inferior to those in CC. The periods children have been confined, their chronological age and their age at the time of admittance greatly influence these results. The differences between IC and CC become important in the IC groups with less than 6 months of confinement and with more than 24 months, in the groups of 4-year-old children and in the ones admitted before 1 year of age or after 4 years of age. In all parameters studied, the differences with CC in girls are more significant than in boys.

Age Factors↗
PubMed1975

Removal of olfactory bulbs in rats of different ages: repercussion on some metabolic constants.

The object of this investigation is to study effects of bulbectomy on female rats operated on at 15 and 30 days of age (prepubescent), 50 days (pubescent) and 120 days (adult), with respect to various parameters: these comprise corporal weight, liver weight, blood sugar, liver glycogen, glucose tolerance test and serum free fatty acid. Results were as follows. Body weight: in all groups this was significantly less than in controls except for rats operated on at adult age. Liver weight: (% of body weight) decreases in all groups, but significantly only in animals operated on when 15 days old. Blood sugar: significantly lessened in rats operated on when 30 and 120 days old. Liver glycogen: lessens in rats operated on at 30 and 120 days of age, but significantly only in the former. Glucose tolerance test: the coefficient k is found to increase in rats operated on at 15, 30 and 120 days of age; there is a significant increase in the first two groups. Serum free fatty acids: no marked alterations in any of the groups.

Aging↗