Role of maternal adrenal glands on the developing serotoninergic and aminoacidergic systems of the postnatal rat brain.

Serotonin, gamma-aminobutyric acid and glutamate, which are regulated by glucocorticoids in the central nervous system, are involved in neuroendocrine functions and the development of the brain. The present study investigates the effect of maternal adrenalectomy on the developing serotoninergic, GABAergic and glutamatergic systems. Neurotransmitter levels were measured in four brain areas of both male and female offspring on postnatal days 1, 8, 12 and 22.

Acute noise stress, ACTH administration, and blood pressure alteration.

Two groups of male Wistar rats were submitted to a single noise exposure (2640 Hz, 30 W, 102 dB, 15 min) (St group) or to a single dose of ACTH (1.5 IU/100 g b.wt.

Effect of chronic stress in the blood pressure in the rat: ACTH administration.

We have studied the effect of chronic noise stress (St) and ACTH administration (Ac) affecting blood pressure and plasma corticosterone levels in male Wistar rats. Both chronic treatments elicited an increase in plasma corticosterone and blood pressure levels. The blood pressure increased from the first week of treatment period in St and Ac rats and remained high 4 weeks after the end of the stress period.

Behavioral and physiologic effects of early nutrition and social factors in the rat.

Two experimental methods to provoke caloric restriction during suckling were used. Each of the methods utilized two different rat groups: Low Growth (LG) and High Growth (HG). In one method, the groups also differed in a social factor, litter size: crowded (Cr) and control (Co).

Chronic noise stress and dexamethasone administration on blood pressure elevation in the rat.

In order to evaluate the role of ACTH and corticosterone in the elevated blood pressure produced by chronic noise, we have studied the effect of dexamethasone administration on blood pressure. Adrenal response was measured by alterations in plasma corticosterone levels in two experimental groups (Dexamethasone treated rats, Dexamethasone-noise stressed rats) and compared with a Control and a Noise-stressed group. Chronic noise stress with a frequency of 2640 Hz, power of 30 w and duration of 15 min daily was used for 30 consecutive days.