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Endocannabinoid and neuroplasticity-related changes as susceptibility factors in a rat model of posttraumatic stress disorder

Authors :
Laszlo Szente
Gyula Y. Balla
Zoltan K. Varga
Blanka Toth
Laszlo Biro
Zoltan Balogh
Matthew N. Hill
Mate Toth
Eva Mikics
Mano Aliczki
Source :
Neurobiology of Stress, Vol 32, Iss , Pp 100662- (2024)
Publication Year :
2024
Publisher :
Elsevier, 2024.

Abstract

Traumatic experiences result in the development of posttraumatic stress disorder (PTSD) in 10–25% of exposed individuals. While human clinical studies suggest that susceptibility is potentially linked to endocannabinoid (eCB) signaling, neurobiological PTSD susceptibility factors are poorly understood. Employing a rat model of contextual conditioned fear, we characterized distinct resilient and susceptible subpopulations based on lasting generalized fear, a core symptom of PTSD. In these groups, we assessed i.) eCB levels by mass spectrometry and ii.) expression variations of eCB system- and iii.) neuroplasticity-related genes by real-time quantitative PCR in the circuitry relevant in trauma-induced changes. Furthermore, employing unsupervised and semi-supervised machine learning based statistical analytical models, we assessed iv.) gene expression patterns with the most robust predictive power regarding PTSD susceptibility. According to our findings, in our model, generalized fear responses occurred with sufficient variability to characterize distinct resilient and susceptible subpopulations. Resilient subjects showed elevated prelimbic and lower ventral hippocampal levels of eCB 2-arachidonoyl-glycerol (2-AG) compared to resilient and non-shocked control subjects. Ventral hippocampal 2-AG content positively correlated with the strength of fear generalization. Furthermore, susceptibility was associated with i.) prefrontal, hippocampal and amygdalar neuronal hypoactivity, ii.) marked decrease in the expression of genes of transcription factors modulating neuroplasticity and iii.) an altered expression pattern of eCB-related genes, including enzymes involved in eCB metabolism. Unsupervised and semi-supervised statistical approaches highlighted that hippocampal gene expression patterns possess strong predictive power regarding susceptibility. Taken together, the marked eCB and neuroplasticity changes in susceptible individuals associated with abnormal activity patterns in the fear circuitry possibly contribute to context coding deficits, resulting in generalized fear.

Details

Language :
English
ISSN :
23522895
Volume :
32
Issue :
100662-
Database :
Directory of Open Access Journals
Journal :
Neurobiology of Stress
Publication Type :
Academic Journal
Accession number :
edsdoj.4fde5a8b5b8e48a5b96424186a73af1b
Document Type :
article
Full Text :
https://doi.org/10.1016/j.ynstr.2024.100662