Neonatal footshock stress alters adult behavior and hippocampal corticosteroid receptors

To determine the effects of stress early in life on adult behavior and hippocampal corticosteroid receptors, rats were exposed to footshocks (0.8 mA, 60 times/day, randomly apart) on postnatal days 14, 17 and 20. When they reached 6 months of age, neurobehavioral alterations were measured. The footshock-experienced rats learned more rapidly in the autoshaped learning test than similarly handled controls. They also stabilized more quickly after exposure to a novel environment than the handled controls, but only at the same rate as animals which had not been handled except for weighing. The density of [H-3]dexamethasone binding sites increased and that of [H-3]corticosterone binding sites decreased in the hippocampi of these rats. These results indicate that early life stress results in altered behavior and hippocampal corticosteroid receptors at adulthood, and suggest that the mineralocorticoid and the glucocorticoid receptors are differentially regulated by early life stress. (C) 1999 Lippincott Williams & Wilkins.