Social isolation in male rats at weaning results in reduced basal levels of the neuroactive steroid allopregnanolone (AP) in the brain and plasma as well as in increased anxiety-like behavior. We now show that socially isolated female rats also manifest a reduced basal cerebrocortical concentration of AP as well as an anxiety-like profile in the elevated plus-maze and Vogel’s conflict tests compared with group-housed (GH) con trols. In contrast, despite the fact that they were raised under normal conditions, adult male offspring of male and female rats subjected to social isolation before mating exhibited an increased basal cerebrocortical level of AP but no difference in emotional reactivity compared with the offspring of GH parents. These animals also showed a blunted AP release induced by foot-shock stress compared to GH offspring. In order to understand this mechanism of resilience to stress, in socially isolated dams we next evaluated the pattern of maternal care and hormonal plasmatic levels of oxytocin, vasopressin and estradiol during pregnancy and after delivery. The results indicate that socially isolated dams did not differ either in the total frequency of licking-grooming and arched-back nursing from GH dams during the first 8 days post partum than in hormonal pattern measured during pregnancy, 3 and 8 days after delivery. Our results suggest that dams hormonal levels and their behavior may be not revelant for stress responsiveness in their offspring.
Altered stress responsiveness and hypothalamic pituitary - adrenal axis function in offspring of socially isolated rats
GARAU, ANNA;BIGGIO, FRANCESCA;BOERO, GIORGIA;SERRA M.
2013-01-01
Abstract
Social isolation in male rats at weaning results in reduced basal levels of the neuroactive steroid allopregnanolone (AP) in the brain and plasma as well as in increased anxiety-like behavior. We now show that socially isolated female rats also manifest a reduced basal cerebrocortical concentration of AP as well as an anxiety-like profile in the elevated plus-maze and Vogel’s conflict tests compared with group-housed (GH) con trols. In contrast, despite the fact that they were raised under normal conditions, adult male offspring of male and female rats subjected to social isolation before mating exhibited an increased basal cerebrocortical level of AP but no difference in emotional reactivity compared with the offspring of GH parents. These animals also showed a blunted AP release induced by foot-shock stress compared to GH offspring. In order to understand this mechanism of resilience to stress, in socially isolated dams we next evaluated the pattern of maternal care and hormonal plasmatic levels of oxytocin, vasopressin and estradiol during pregnancy and after delivery. The results indicate that socially isolated dams did not differ either in the total frequency of licking-grooming and arched-back nursing from GH dams during the first 8 days post partum than in hormonal pattern measured during pregnancy, 3 and 8 days after delivery. Our results suggest that dams hormonal levels and their behavior may be not revelant for stress responsiveness in their offspring.
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