IMR Press / JIN / Volume 22 / Issue 4 / DOI: 10.31083/j.jin2204100
Open Access Original Research
Controllable Stress Increases Rapid Eye Movement Sleep in Rats: Regulation by the Central Nucleus of the Amygdala
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1 Sleep Research Laboratory, Center for Integrative Neuroscience and Inflammatory Diseases, Pathology and Anatomy, Eastern Virginia Medical School, Norfolk, VA 23507, USA
2 Sleep Medicine Center, Mental Health Center, Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, 610041 Chengdu, Sichuan, China
*Correspondence: SanforLD@evms.edu (Larry D. Sanford)
J. Integr. Neurosci. 2023, 22(4), 100; https://doi.org/10.31083/j.jin2204100
Submitted: 23 February 2023 | Revised: 21 April 2023 | Accepted: 16 May 2023 | Published: 20 July 2023
Copyright: © 2023 The Author(s). Published by IMR Press.
This is an open access article under the CC BY 4.0 license.
Abstract

Background: Training with inescapable shock (IS; uncontrollable stressor) is followed by significant decreases in rapid eye movement sleep (REM). However, controllability is important in the effects of stress. We examined the effects of escapable shock (ES; controllable stressor) on sleep and whether the central nucleus of the amygdala (CNA) plays a role in regulating these effects. Methods: Six Wistar rats implanted with a cannula located in CNA underwent two days of ES training (20 shock presentations; 0.5 mA; 5.0 s maximum duration; 1.0 min interstimulus interval). Five days later, they were re-exposed to the shock context. Results: Following shock training, REM was significantly increased in both light and dark periods. Non-REM (NREM) and total sleep (TS) duration were decreased during the light period. Similar effects on REM and NREM were observed following re-exposure to the training context alone. Microinjections of saline into CNA immediately following ES also produced similar increases in REM, whereas microinjections of muscimol (MUS; GABAA (γ-aminobutyric acid) antagonist) subsequent to ES blocked the increases in REM. Conclusions: These data, along with previous work with ES and IS, demonstrate that stressor controllability is important in determining how stress impacts sleep. Moreover, the results of the microinjection study indicate that the effects of ES on REM are regulated through the CNA.

Keywords
amygdala
fear memory
sleep
stress
Funding
MH64827/NIH research
Figures
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