Effects of inescapable stress on LTP in the amygdala versus the dentate gyrus of freely behaving rats

Stress impairs hippocampal long‐term potentiation (LTP), a model of synaptic plasticity that is assumed to underlie memory formation. In the amygdala, little is known about the effects of stress on LTP, or about its longevity. Here we assessed the ability of entorhinal cortex (EC) stimulation to ind...

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Bibliographic Details
Published in:The European journal of neuroscience 2004-04, Vol.19 (7), p.1887-1894
Main Authors: Vouimba, Rose-Marie, Yaniv, Dan, Diamond, David, Richter-Levin, Gal
Format: Article
Language:English
Subjects:
Amygdala - physiology
Animals
basal amygdaloid nucleus
Behavior, Animal
Dentate Gyrus - physiology
Electric Stimulation - methods
Entorhinal Cortex - physiology
Entorhinal Cortex - radiation effects
fear
hippocampus
Immobilization
Long-Term Potentiation - physiology
Long-Term Potentiation - radiation effects
Male
plasticity
Rats
Rats, Wistar
Stress, Psychological - physiopathology
Synaptic Transmission - physiology
Time Factors
Wakefulness - drug effects
Wakefulness - physiology
Wistar rats
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Summary:Stress impairs hippocampal long‐term potentiation (LTP), a model of synaptic plasticity that is assumed to underlie memory formation. In the amygdala, little is known about the effects of stress on LTP, or about its longevity. Here we assessed the ability of entorhinal cortex (EC) stimulation to induce LTP simultaneously in the basal amygdaloid nucleus (B) and in the dentate gyrus (DG) of freely behaving Wistar rats. We also tested whether LTP persists over days. Once established, we investigated the effects of acute vs. repeated inescapable stressful experiences on LTP in both structures. Results show that B, like DG, sustained LTP for 7 days. Furthermore, a single exposure to moderate stress facilitated LTP in B but did not affect DG LTP. Stress re‐exposure inhibited LTP in DG but only long‐lasting LTP (>3 days) in B. Behaviourally, animals exhibited a higher immobility when re‐exposed to the stressor than with a single/first exposure. These data support a role for B in memory storage. Furthermore, they support a differential involvement of the amygdala and hippocampus in memory formation and storage depending on the emotional characteristics of the experience.
ISSN:0953-816X
1460-9568
DOI:10.1111/j.1460-9568.2004.03294.x