title: Selectively Bred Rats Provide a Unique Model of Vulnerability to PTSD-Like Behavior and Respond Differentially to FGF2 Augmentation Early in Life.
abstract: Individuals respond differently to traumatic experiences, including their propensity to develop posttraumatic stress disorder (PTSD). Understanding individual differences in PTSD vulnerability will allow the development of improved prevention and treatment options. Here we characterized fear conditioning and extinction in rats selectively bred for differences in their locomotor response to a novel environment. Selectively bred high-responder (bHR) and low-responder (bLR) male rats are known to differ in their emotional reactivity on a range of measures of spontaneous anxiety- and depressive-like behaviors. We demonstrate that bHRs have facilitated extinction learning and retention compared with outbred Sprague Dawley rats, whereas bLRs show reduced extinction learning and retention. This indicates that bLRs are more vulnerable to PTSD-like behavior. Fibroblast growth factor 2 (FGF2) has previously been implicated in the development of these behavioral phenotypes and facilitates extinction learning in outbred animals, therefore we examined the effects of early-life FGF2 on bHR and bLR behavior. FGF2 administered on the day after birth facilitated extinction learning and retention in bHRs, but not in bLRs or control rats, during adulthood. This indicates that, under the current fear conditioning paradigm, early-life FGF2 has protective effects only in resilient animals. This stands in contrast to FGF2's ability to protect vulnerable animals in milder tests of anxiety. These results provide a unique animal model of individual differences in PTSD-like behavior, allowing the study of genetic, developmental, and environmental factors in its expression.
authors.affiliation: Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA.|Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Katherine E
authors.identifier: http://orcid.org/0000-0001-8615-207X
authors.initials: KE
authors.lastname: Prater
authors.affiliation: Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA.|Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Elyse L
authors.initials: EL
authors.lastname: Aurbach
authors.affiliation: Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Hanna K
authors.initials: HK
authors.lastname: Larcinese
authors.affiliation: Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Taylor N
authors.initials: TN
authors.lastname: Smith
authors.affiliation: Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Cortney A
authors.initials: CA
authors.lastname: Turner
authors.affiliation: Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Blandino
authors.affiliation: Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Stanley J
authors.initials: SJ
authors.lastname: Watson
authors.affiliation: Department of Psychology, Texas A&M University, College Station TX, USA.
authors.forename: Stephen
authors.identifier: http://orcid.org/0000-0002-9342-7411
authors.initials: S
authors.lastname: Maren
authors.affiliation: Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Huda
authors.initials: H
authors.lastname: Akil
mesh_terms: D000375:Aging / Q000187:drug effects; D000818:Animals; D001522:Behavior, Animal; D003213:Conditioning, Psychological; D004198:Disease Susceptibility / Q000523:psychology*; D004777:Environment; D005108:Extinction, Psychological; D005239:Fear; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology*; D007206:Individuality; D008297:Male; D009043:Motor Activity; D051381:Rats; D011919:Rats, Inbred Strains; D013313:Stress Disorders, Post-Traumatic / Q000523:psychology*
chemical_list: D016222:Fibroblast Growth Factor 2