Sex differences and estropausal phase effects on water maze performance inaged rats

An age-related decline in memory has been reported in male rats; however, t here are few studies that have addressed these changes in aged female rats. In young female rats, hormonal cycles influence behavior. By the age of 22 months most female rats have not had regular hormonal cycles for at least 9 months. In the current study we examined how the hormonal status (persist ent estrus and pseudopregnant) of the aged (22-24 months) female rat (Long Evans) influenced performance on a spatial version of the Morris water maze and compared this to aged male rats. Aged females in persistent estrus sho wed better performance on the water maze than both aged females that were p seudopregnant and aged males. Thus, postestropausal hormonal status may inf luence the course of aging in females. (C) 2000 Academic Press.