EFFECT OF ORAL CORTICOSTERONE ADMINISTRATION ON LOCOMOTOR DEVELOPMENTOF NEONATAL AND JUVENILE RATS

In order to simulate the elevated corticosteroid levels to which offsp ring of stressed women may be subjected, rat pups were treated daily w ith two levels of oral corticosterone from the 2nd to the 15th postnat al day. The rat pups were subjected to swimming tests from their 8th p ostnatal day to examine their neuromuscular development and learning a bilities. The locomotor performance of corticosterone-treated groups w as similar to that of controls but its development was delayed, which demonstrates that even relatively low levels of corticosterone have a significant negative influence on the maturation and learning ability of neonatal rat pups. This indicates that the glucocorticoid levels to which suckling neonates (for example, children of women suffering fro m stress) might be exposed could modify the complex integrated neuromu scular adaptive mechanisms involved in normal locomotor development.