title: Peripheral infection and aging interact to impair hippocampal memory consolidation.
abstract: 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.
authors.affiliation: Department of Psychology and Center for Neuroscience, University of Colorado at Boulder, Campus Box 345, Boulder, CO 80309-0345, USA. rbarr@psych.colorado.edu
authors.forename: Ruth M
authors.initials: RM
authors.lastname: Barrientos
authors.forename: Emily A
authors.initials: EA
authors.lastname: Higgins
authors.forename: Joseph C
authors.initials: JC
authors.lastname: Biedenkapp
authors.forename: David B
authors.initials: DB
authors.lastname: Sprunger
authors.forename: Karli J
authors.initials: KJ
authors.lastname: Wright-Hardesty
authors.forename: Linda R
authors.initials: LR
authors.lastname: Watkins
authors.forename: Jerry W
authors.initials: JW
authors.lastname: Rudy
authors.forename: Steven F
authors.initials: SF
authors.lastname: Maier
mesh_terms: 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
chemical_list: D007375:Interleukin-1