The international journal of neuropsychopharmacology
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Int. J. Neuropsychopharmacol. · May 2008
Post-traumatic stress behavioural responses in inbred mouse strains: can genetic predisposition explain phenotypic vulnerability?
Clinical studies of twin pairs and families of post-traumatic stress disorder (PTSD) patients raise questions as to possible genetic predisposition to PTSD. Studies using isogenic animal populations exposed to a stress paradigm could elucidate the relative contributions of genotype and environment to endophenotypic expression. The prevalence of individuals displaying severely compromised behavioural responses to predator scent stress (PSS) was assessed in six inbred strains of mice in an animal model of PTSD that classifies individuals into groups according to the degree of their behavioural response. ⋯ Although strain-specific differences in anxiety-like behaviours were demonstrated, the results revealed a significant degree of individual variability in response patterns within each of the inbred strains, yielding a baseline heritability factor for anxiety-like behaviours of 30%, but only 10% for response to stress exposure. Baseline anxiety-like behaviours were found not to be predictive of post-exposure behavioural responses. The response of the individual to stress is multifactorial and environmental factors play a predominant role in characterizing the individual response to stress exposure, although there are significant genetic underpinnings.