title: Coping style and stress hormone responses in genetically heterogeneous rats: comparison with the Roman rat strains.
abstract: The purpose of the present study was to evaluate for the first time the stress-induced hypothalamus-pituitary-adrenal (HPA), adrenocorticotropic hormone (ACTH), corticosterone and prolactin responses of the National Institutes of Health genetically heterogeneous rat stock (N/Nih-HS rats) in comparison with responses of the relatively high and low stress-prone Roman Low- (RLA-I) and High-Avoidance (RHA-I) rat strains. The same rats were also compared (experiment 1) with respect to their levels of unconditioned anxiety (elevated zero-maze test), novelty-induced exploratory behavior, conditioned fear and two-way active avoidance acquisition. In experiment 2, naive rats from these three strains/stocks were evaluated for "depressive-like" behavior in the forced swimming test. N/Nih-HS and RLA-I rats showed significantly higher post-stress ACTH, corticosterone and prolactin levels than RHA-I rats. N/Nih-HS rats also presented the highest context-conditioned freezing responses, extremely poor two-way avoidance acquisition and very low novelty-induced exploratory behavior. Experiment 2 showed that, compared to RHA-I rats, N/Nih-HS and RLA-I rats displayed significantly less struggling (escape-directed) and increased immobility responses in the forced swimming test. Factor analysis of data from experiment 1 showed associations among behavioral and hormonal responses, with a first factor comprising high loadings of elevated zero-maze variables and lower loadings of conditioned fear, two-way avoidance acquisition and hormonal measures, while a second factor mainly grouped conditioned fear and two-way avoidance acquisition with novelty-induced exploration and post-stress prolactin. Thus, regarding their anxiety/fearfulness, passive coping style, "depressive-like" and stress-induced hormonal responses the N/Nih-HS rats resemble the phenotype profiles of the relatively high-anxious and stress-prone RLA-I rat strain.
authors.affiliation: Medical Psychology Unit, Department of Psychiatry & Forensic Medicine, Institute of Neurosciences, School of Medicine, Autonomous University of Barcelona, 08193 Bellaterra, Barcelona, Spain.
authors.forename: Sira
authors.initials: S
authors.lastname: Díaz-Morán
authors.forename: Marta
authors.initials: M
authors.lastname: Palència
authors.forename: Carme
authors.initials: C
authors.lastname: Mont-Cardona
authors.forename: Toni
authors.initials: T
authors.lastname: Cañete
authors.forename: Gloria
authors.initials: G
authors.lastname: Blázquez
authors.forename: Esther
authors.initials: E
authors.lastname: Martínez-Membrives
authors.forename: Regina
authors.initials: R
authors.lastname: López-Aumatell
authors.forename: Adolf
authors.initials: A
authors.lastname: Tobeña
authors.forename: Alberto
authors.initials: A
authors.lastname: Fernández-Teruel
mesh_terms: D000223:Adaptation, Psychological / Q000502:physiology*; D000324:Adrenocorticotropic Hormone / Q000097:blood; D000818:Animals; D001362:Avoidance Learning / Q000502:physiology; D003345:Corticosterone / Q000097:blood; D005106:Exploratory Behavior / Q000502:physiology; D018740:Genetic Heterogeneity; D046353:Immobility Response, Tonic / Q000502:physiology; D008297:Male; D018782:Maze Learning / Q000502:physiology; D011388:Prolactin / Q000097:blood; D051381:Rats; D011919:Rats, Inbred Strains / Q000502:physiology* / Q000523:psychology*; D013045:Species Specificity; D013315:Stress, Psychological / Q000097:blood* / Q000523:psychology*
chemical_list: D000324:Adrenocorticotropic Hormone; D011388:Prolactin; D003345:Corticosterone