The immediate early gene Arc is associated with behavioral resilience to stress exposure in an animal model of posttraumatic stress disorder.
Mechanisms involved in adaptative and maladaptive changes in neural plasticity and synaptic efficacy in various brain areas are pivotal to understanding the physiology of the response to stress and the pathophysiology of posttraumatic stress disorder (PTSD). Activity-regulated cytoskeletal-associated protein (Arc) is an effector immediate early gene (IEG) which has direct effects on intracellular homeostatic functions. Increased expression of Arc has been associated with increased neuronal activity and with consolidation of long-term memory. It may thus play an important role in mediating experience-induced reorganization and/or development of synaptic connections. This study sought to characterize the pattern of expression of mRNA for the Arc gene in selected brain areas of test subjects classified according to their individual pattern of behavioral response to a stressor, correlated with circulating levels of corticosterone (as a physiological marker of stress response). The hippocampal CA1 and CA3 subregions of individuals whose behavior was minimally or partially disrupted in response to predator scent stress demonstrated significantly increased levels of mRNA for Arc, compared to unexposed controls. The group whose behavior was severely disrupted demonstrated no such upregulation. Consistent with the hypothesis that the Arc gene has a promoting effect on neuronal function and/or structural changes, the lack of Arc expression in the behaviorally and physiologically more severely affected individuals raises the possibility that Arc may be associated with resilience and/or recovery after stress exposure.
Kozlovsky
Nitsan
N
Ministry of Health Beer-Sheva Mental Health Center, Anxiety and Stress Research Unit, Faculty of Health Sciences, Ben-Gurion University of the Negev, PO Box 4600, Beer-Sheva 84170, Israel.
Matar
Michael A
MA
Kaplan
Zeev
Z
Kotler
Moshe
M
Zohar
Joseph
J
Cohen
Hagit
H
D000222:Adaptation, Physiological / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D002415:Cats; D003345:Corticosterone / Q000097:blood; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D004195:Disease Models, Animal; D005786:Gene Expression Regulation / Q000502:physiology*; D006624:Hippocampus / Q000378:metabolism; D008297:Male; D018782:Maze Learning; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013223:Statistics as Topic; D013313:Stress Disorders, Post-Traumatic / Q000097:blood / Q000235:genetics / Q000473:pathology / Q000503:physiopathology*; D013315:Stress, Psychological / Q000097:blood / Q000235:genetics / Q000503:physiopathology*; D013997:Time Factors
D003598:Cytoskeletal Proteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; C092069:activity regulated cytoskeletal-associated protein; D003345:Corticosterone