Estradiol enhances retention but not organization of hippocampus-dependent memory in intact male mice
Psychoneuroendocrinology. 2016-07-01; 69: 77-89
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1. Psychoneuroendocrinology. 2016 Jul;69:77-89. doi: 10.1016/j.psyneuen.2016.03.014.
Epub 2016 Mar 21.
Estradiol enhances retention but not organization of hippocampus-dependent memory
in intact male mice.
Al Abed AS(1), Sellami A(1), Brayda-Bruno L(1), Lamothe V(1), Noguès X(1), Potier
M(1), Bennetau-Pelissero C(1), Marighetto A(2).
(1)Neurocentre Magendie, INSERM U1215, F-33000 Bordeaux, France; Université de
Bordeaux, F-33000 Bordeaux, France.
(2)Neurocentre Magendie, INSERM U1215, F-33000 Bordeaux, France; Université de
Bordeaux, F-33000 Bordeaux, France. Electronic address:
Because estrogens have mostly been studied in gonadectomized females, effects of
chronic exposure to environmental estrogens in the general population are
underestimated. Estrogens can enhance hippocampus-dependent memory through the
modulation of information storage. However, declarative memory, the
hippocampus-dependent memory of facts and events, demands more than abilities to
retain information. Specifically, memory of repetitive events of everyday life
such as « where I parked » requires abilities to organize/update memories to
prevent proactive interference from similar memories of previous « parking
events ». Whether such organizational processes are estrogen-sensitive is unknown.
We here studied, in intact young and aged adult mice, drinking-water (1μM)
estradiol effects on both retention and organizational components of
hippocampus-dependent memory, using a radial-maze task of everyday-like memory.
Demand on retention vs organization was manipulated by varying the time-interval
separating repetitions of similar events. Estradiol increased performance in
young and aged mice under minimized organizational demand, but failed to improve
the age-associated memory impairment and diminished performance in young mice
under high organizational demand. In fact, estradiol prolonged mnemonic retention
of successive events without improving organization abilities, hence resulted in
more proactive interference from irrelevant memories. c-Fos imaging of
testing-induced brain activations showed that the deterioration of young memory
was associated with dentate gyrus dysconnectivity, reminiscent of that seen in
aged mice. Our findings support the view that estradiol is promnesic but also
reveal that such property can paradoxically impair memory. These findings have
important outcomes regarding health issues relative to the impact of
environmental estrogens in the general population.
Copyright © 2016 Elsevier Ltd. All rights reserved.
PMID: 27038677 [Indexed for MEDLINE]