Peripheral infection and aging interact to impair hippocampal memory consolidation.
We report that a peripheral injection of Escherichia coli produces both anterograde and retrograde amnesia in 24 month old, but not 3 month old rats for memories that depend on the hippocampus, that is, memory of context, contextual fear, and place learning. The anterograde effect was restricted to measures of long-term memory. Short-term memory was not affected, nor did E. coli produce amnesia for auditory-cue fear conditioning. There were no age related effects on memory in vehicle-treated rats. In addition to these age-related cognitive effects of E.coli, we report that it produced a marked increased in IL-1beta levels in the hippocampus, but not in parietal cortex or serum. These findings support the hypothesis that age is a vulnerability factor that increases the likelihood that an immune challenge will produce a cognitive impairment. It is possible that this cognitive vulnerability is mediated by age-related changes in the glial environment that results in an exaggerated brain pro-inflammatory response to infection.
Barrientos
Ruth M
RM
Department of Psychology and Center for Neuroscience, University of Colorado at Boulder, Campus Box 345, Boulder, CO 80309-0345, USA. rbarr@psych.colorado.edu
Higgins
Emily A
EA
Biedenkapp
Joseph C
JC
Sprunger
David B
DB
Wright-Hardesty
Karli J
KJ
Watkins
Linda R
LR
Rudy
Jerry W
JW
Maier
Steven F
SF
D000161:Acoustic Stimulation; D000375:Aging / Q000502:physiology* / Q000523:psychology; D020324:Amnesia, Anterograde / Q000523:psychology; D000648:Amnesia, Retrograde / Q000523:psychology; D000818:Animals; D003213:Conditioning, Psychological / Q000502:physiology; D004927:Escherichia coli Infections / Q000276:immunology / Q000503:physiopathology* / Q000523:psychology; D005239:Fear; D006624:Hippocampus / Q000503:physiopathology*; D007375:Interleukin-1 / Q000378:metabolism; D008297:Male; D018782:Maze Learning / Q000502:physiology; D008569:Memory Disorders / Q000209:etiology / Q000503:physiopathology* / Q000523:psychology; D051381:Rats
D007375:Interleukin-1