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Persistent inhibition of hippocampal long‐term potentiation in vivo by learned helplessness stress

Persistent inhibition of hippocampal long‐term potentiation in vivo by learned helplessness stress The persistent cognitive disruptive effects of stress have been strongly implicated in the pathophysiology of depression and post‐traumatic stress disorder. Here we examined factors influencing the time course of recovery from the inhibitory effect of acute inescapable stressors on the ability to induce long‐term potentiation (LTP) in the dorsal hippocampus in vivo. We tested different forms of LTP, different stressors and different inbred strains of rats. Acute elevated platform stress completely, but transiently (<3 h), inhibited induction of both NMDA receptor‐dependent LTP induced by a standard high frequency (200 Hz) conditioning stimulus and an additional LTP that required voltage‐dependent Ca2+ channel activation triggered by strong (400 Hz) conditioning stimulation. In contrast, acute inescapable footshock stress, used to study learned helplessness, inhibited LTP for at least 4 weeks. Contrary to expectations, there was no clear relationship between the ability of the footshock to trigger helpless behavior, a model of stress‐induced depression, and the magnitude of LTP inhibition. Moreover, LTP did not appear to be affected by genetic susceptibility to learned helplessness, a model of genetic vulnerability to depression. This long‐lasting synaptic plasticity disruption may underlie persistent impairment of hippocampus‐dependent cognition by excessive acute inescapable stress. © 2009 Wiley‐Liss, Inc. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Hippocampus Wiley

Persistent inhibition of hippocampal long‐term potentiation in vivo by learned helplessness stress

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References (54)

Publisher
Wiley
Copyright
Copyright © 2009 Wiley‐Liss, Inc.
ISSN
1050-9631
eISSN
1098-1063
DOI
10.1002/hipo.20677
pmid
19623539
Publisher site
See Article on Publisher Site

Abstract

The persistent cognitive disruptive effects of stress have been strongly implicated in the pathophysiology of depression and post‐traumatic stress disorder. Here we examined factors influencing the time course of recovery from the inhibitory effect of acute inescapable stressors on the ability to induce long‐term potentiation (LTP) in the dorsal hippocampus in vivo. We tested different forms of LTP, different stressors and different inbred strains of rats. Acute elevated platform stress completely, but transiently (<3 h), inhibited induction of both NMDA receptor‐dependent LTP induced by a standard high frequency (200 Hz) conditioning stimulus and an additional LTP that required voltage‐dependent Ca2+ channel activation triggered by strong (400 Hz) conditioning stimulation. In contrast, acute inescapable footshock stress, used to study learned helplessness, inhibited LTP for at least 4 weeks. Contrary to expectations, there was no clear relationship between the ability of the footshock to trigger helpless behavior, a model of stress‐induced depression, and the magnitude of LTP inhibition. Moreover, LTP did not appear to be affected by genetic susceptibility to learned helplessness, a model of genetic vulnerability to depression. This long‐lasting synaptic plasticity disruption may underlie persistent impairment of hippocampus‐dependent cognition by excessive acute inescapable stress. © 2009 Wiley‐Liss, Inc.

Journal

HippocampusWiley

Published: Jun 1, 2010

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