Effect of early scream sound stress on learning and memory in female rats

Abstract

To investigate the effect of early scream sound stress on the ability of spatial learning and memory, the levels of norepinephrine (NE) and corticosterone (CORT) in serum, and the morphology of adrenal gland. Female Sprague-Dawley (SD) rats were treated daily with scream sound from postnatal day 1(P1) for 21 d. Morris water maze was used to measure the spatial learning and memory ability. The levels of serum NE and CORT were determined by radioimmunoassay. Adrenal gland of SD rats was collected and fixed in formalin, and then embedded with paraffin. The morphology of adrenal gland was observed by HE staining. Exposure to early scream sound decreased latency of escape and increased times to cross the platform in Morris water maze test (P<0.05). The levels of serum NE was significantly elevated, with an obvious tendency in the increase of CORT level (P<0.05). The morphology of adrenal gland was also influenced. Newborn female rats subjected to scream sound stress can enhance spatial learning and memory ability in adulthood, which is related to activation of the hypothalamo-pituitary-adrenal axis and sympathetic nervous system.