AJP - Regulatory, Integrative and Comparative Physiology, Vol 273, Issue 4 1332-R1338, Copyright © 1997 by American Physiological Society
Long-term effects of maternal deprivation on the corticosterone response to stress in rats
D. Suchecki and S. Tufik
Department of Psychobiology, Universidade Federal de Sao Paulo, Brazil.
Twenty-four hours of maternal deprivation result in activation of the
infant rat's adrenocortical axis. In the present study we examined the
long-term effects of maternal deprivation on the corticosterone (Cort)
response to stress. Pups were maternally deprived (Dep) on postnatal day
(PND) 11 and tested immediately (PND 12) or returned to their mothers and
tested at later ages. Testing consisted of a time course of the Cort
response to a saline injection (5, 15, 30, and 60 min). At PND 12, the
response of Dep pups was higher than that of nondeprived (non-Dep) pups. No
group differences were observed at PND 16 and 22. On PND 30, Dep rats
showed lower Cort levels than non-Dep pups at 0, 5, and 30 min after
saline. At PND 60, non-Dep females showed higher Cort levels than males at
5, 15, and 30 min. This gender difference for Dep pups was observed only at
5 min. Male and female Dep animals presented lower Cort levels than non-Dep
counterparts at 60 and 30 min after saline, respectively. These findings
indicate that maternal deprivation effects on Cort secretion are long
lasting. Dep rats showed a smaller adrenal response to stress at PND 30,
whereas as adults the stress response was similar but the turnoff was
different.
