Ovarian hormones and cognition in the aged female rat: I. Long-term, but not short-term, ovariectomy enhances spatial performance.
Although research suggests that ovariectomy (ovx) is detrimental to spatial cognition in young rats, little work has evaluated the cognitive effects of ovx in aged rats. The authors investigated the effects of ovx in aged rats using the water radial-arm maze. In Study 1, young rats and aged rats receiving ovx 1.5 months before testing outperformed aged rats receiving sham surgery or ovx 21 days before testing. In Study 2, young rats and aged rats receiving ovx 2.0 or 6.0 months before testing outperformed aged sham rats. Aged rats exhibited estradiol and elevated progesterone levels comparable to those of young rats. The findings suggest that 1.5-6.0 months, but not 21 days, of ovx improves spatial memory in aged rats. The hypothesis that long-term ovarian hormone loss is detrimental to spatial memory in aged rats was not supported. The authors hypothesize that removal of elevated progesterone levels is related to the ovx-induced cognitive enhancement.
Bimonte-Nelson
Heather A
HA
Department of Physiology and Neuroscience, Medical University of South Carolina, Charleston 29425, USA. bimonte@musc.edu
Singleton
Rachel S
RS
Hunter
Christopher L
CL
Price
Kimber L
KL
Moore
Alfred B
AB
Granholm
Ann-Charlotte E
AC
D000375:Aging / Q000502:physiology*; D000818:Animals; D003071:Cognition / Q000502:physiology; D004958:Estradiol / Q000097:blood*; D005260:Female; D018782:Maze Learning / Q000502:physiology*; D010052:Ovariectomy; D011374:Progesterone / Q000097:blood*; D051381:Rats; D011916:Rats, Inbred F344; D012153:Retention, Psychology / Q000502:physiology*; D013028:Space Perception / Q000502:physiology*; D013037:Spatial Behavior / Q000502:physiology
D011374:Progesterone; D004958:Estradiol