Mechanisms Underlying Footshock and Psychological Stress-Induced Abrupt Awakening from Posttraumatic "Nightmares"

Abstract

Background: Posttraumatic nightmares are a highly prevalent and distressing symptom of posttraumatic stress disorder (PTSD), but have been the subject of limited phenomenological investigations. Methods: We utilized a communication box to establish PTSD symptoms in rats through exposure to footshock stress (FS) and psychological stress (PS). The immunohistochemical test and high-performance liquid chromatography with electrochemical detection were used to detect the activity and monoamine levels in the rats' arousal systems. Results: Twenty-one days after traumatic stress, 14.17% of FS and 12.5% of PS rats exhibited startled awakening, and the same rats showed hyperfunction of the locus coeruleus/noradrenergic system and hypofunction of the perifornical nucleus/orexinergic system. Changes in serotonin levels in the dorsal raphe nucleus showed opposite trends in the FS and PS rats that were startled awake. No differences were found in other sleep/arousal systems. Conclusion: These results suggest that different clinically therapeutic strategies should be considered to treat different trauma-induced posttraumatic nightmares.