Summary: Chronic administration of corticosterone impairs spatial
reference memory before spatial working memory in rats
and B.J. Andersona,b,*
Program in Neurobiology, SUNY Stony Brook, Stony Brook, NY 11790-5230, USA
Department of Psychology, SUNY Stony Brook, Stony Brook, NY 11790-5230, USA
Received 22 October 2001; revised 31 December 2002; accepted 1 January 2003
Corticosterone (CORT), the predominant glucocorticoid in rodents, elevated for 21 days damages hippocampal subregion CA3.
We tested the hypothesis that CORT would impair spatial memory, a hippocampal function. In each of the three experiments, rats
received daily, subcutaneous injections of either CORT (26.8 mg/kg body weight in sesame oil) or sesame oil vehicle alone (VEH).
CORT given for 21 or 56 days effectively attenuated body weight gain and reduced selective organ and muscle weights. All be-
havioral testing was done on tasks that are minimally stressful and avoid deprivation. For each experiment, testing commenced 24 h
after the last injection. CORT given for 21 days did not impair spatial working memory in the Y-maze (Experiments 1 and 2). After
56-day administration of CORT, spatial working memory was impaired in the Y-maze (Experiment 2). CORT given for 21 days also