Background
Chronic stress is a major health concern, often leading to depression, anxiety, or
when severe enough, posttraumatic stress disorder. While many studies demonstrate
that the amygdala is hyperresponsive in patients with these disorders, the cellular
neurophysiological effects of chronic stress on the systems that underlie psychiatric
disorders, such as the amygdala, are relatively unknown.
Methods
In this study, we examined the effects of chronic stress on the activity and excitability
of amygdala neurons in vivo in rats. We used in vivo intracellular recordings from
single neurons of the lateral amygdala (LAT) to measure neuronal properties and determine
the cellular mechanism for the effects of chronic stress on LAT neurons.
Results
We found a mechanism for the effects of chronic stress on amygdala activity, specifically
that chronic stress increased excitability of LAT pyramidal neurons recorded in vivo.
This hyperexcitability was caused by a reduction of a regulatory influence during
action potential firing, facilitating LAT neuronal activity. The effects of stress
on excitability were occluded by agents that block calcium-activated potassium channels
and reversed by pharmacological enhancement of calcium-activated potassium channels.
Conclusions
These data demonstrate a specific channelopathy that occurs in the amygdala after
chronic stress. This enhanced excitability of amygdala neurons after chronic stress
may explain the observed hyperresponsiveness of the amygdala in patients with posttraumatic
stress disorder and may facilitate the emergence of depression or anxiety in other
patients.
Key Words
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Article info
Publication history
Published online: April 09, 2010
Accepted:
February 9,
2010
Received in revised form:
January 26,
2010
Received:
November 13,
2009
Identification
Copyright
© 2010 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.
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- Amygdala Activity, Fear, and Anxiety: Modulation by StressBiological PsychiatryVol. 67Issue 12
- PreviewOver the past approximately 30 years, the neuroscience community has made terrific strides in its understanding of the small region in the temporal lobe named for its peculiar almond shape, the amygdala. This area now provides among the best examples of how neural circuits control specific behaviors. In terms of our depth of understanding of its afferent and efferent connections, the role of incoming signals in modulating emotion-related behavior, and the functional and anatomic results of its projection patterns, the detailed understanding of the amygdala is unsurpassed.
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