Vol.:(0123456789) 1 3 Behav Genet DOI 10.1007/s10519-017-9854-2 ORIGINAL RESEARCH Conservation of Phenotypes in the Roman High- and Low- Avoidance Rat Strains After Embryo Transfer Cristóbal Río-Álamos 1  · Cristina Gerbolés 1  · Carles Tapias-Espinosa 1  · Daniel Sampedro-Viana 1  · Ignasi Oliveras 1  · Ana Sánchez-González 1  · Toni Cañete 1  · Gloria Blázquez 1  · María del Mar López 2  · Carlos Baldellou 2  · Pedro J. Otaegui 2  · Adolf Tobeña 1  · Alberto Fernández-Teruel 1   Received: 22 February 2017 / Accepted: 3 June 2017 © Springer Science+Business Media, LLC 2017 Keywords Roman rat strains · Embryo transfer · Behavioural phenotyping · Two-way active avoidance · Stress-induced corticosterone Introduction The selection of Rattus norvegicus for good versus poor two-way active avoidance acquisition in a shuttle box was originally carried out in Rome and led to the outbred Roman high- (RHA) and low-avoidance (RLA) rat lines (Bignami 1965). From these original lines, the Swiss sub- lines, RHA/Verh and RLA/Verh, were derived in Switzer- land since 1972 (Driscoll and Bättig 1982; Driscoll et al. 1998). Two inbred strains (RHA-I and RLA-I) derived from the original outbred (RHA/Verh and RLA/Verh) lines through “brother × sister” mating, are maintained at the Autonomous University of Barcelona since 1997 (Spain; Dr. A. Fernández-Teruel; Escorihuela et al. 1999; Driscoll et al. 2009), while colonies of the outbred RHA/ RLA rat lines are maintained at Geneva (Switzerland; Dr. T. Steimer; e.g., Steimer and Driscoll 2003) and Cagliari (Italy; Dr. Giorgi and Dr. M.G. Corda; e.g. Giorgi et al. 2007). The acquisition of two-way active avoidance, the cri- terion of bidirectional breeding/selection of RHA and RLA strains/lines, has been shown to be inversely related to anxiety, i.e. the higher the anxiety levels the poorer the acquisition of avoidance responses (e.g., Fernández-Teruel et al. 1991; López-Aumatell et al. 2009a; Díaz-Morán et al. 2012, and references therein). Not surprisingly, therefore, the research conducted with RLA and RHA rats (both from the outbred lines and the inbred strains) over four dec- ades has revealed that anxiety/fearfulness and sensitivity to stress are among the most relevant traits diferentiating Abstract The Roman high- (RHA-I) and low-avoid- ance (RLA-I) rat strains are bi-directionally bred for their good versus non-acquisition of two-way active avoidance, respectively. They have recently been re-derived through embryo transfer (ET) to Sprague–Dawley females to gen- erate specifc pathogen free (SPF) RHA-I/RLA-I rats. Of- spring were phenotyped at generations 1 (G1, born from Sprague–Dawley females), 3 and 5 (G3 and G5, born from RHA-I and RLA-I from G2–G4, respectively), and com- pared with generation 60 from our non-SPF colony. Phe- notyping included two-way avoidance acquisition, context- conditioned fear, open-feld behaviour, novelty-seeking, baseline startle, pre-pulse inhibition (PPI) and stress- induced increase in plasma corticosterone concentration. Post-ET between-strain diferences in avoidance acquisi- tion, context-conditioned freezing and novelty-induced self-grooming are conserved. Other behavioural traits (i.e. hole-board head-dipping, novel object exploration, open- feld activity, startle, PPI) diferentiate the strains at G3–G5 but not at G1, suggesting that the pre-/post-natal environ- ment may have infuenced these co-segregated traits at G1, though further selection pressure along the subsequent generations (G1–G5) rescues the typical strain-related diferences. Edited by Stephen Maxson. * Alberto Fernández-Teruel albert.fernandez.teruel@uab.cat 1 Medical Psychology Unit, Department of Psychiatry and Forensic Medicine, Institute of Neurosciences, School of Medicine, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain 2 Servei d’Estabulari, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain