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The aim of the present study was to obtain further evidence supporting the validity of a new genetically-based rat model for the study of schizophrenia-relevant symptoms. The Roman high- (RHA-I) and low-avoidance (RLA-I) inbred rats have been psychogenetically selected for their rapid versus extremely poor acquisition of the two-way avoidance task in the shuttle box and present two well-differentiated profiles regarding several traits related to anxiety, impulsivity and sensitivity to (dopaminergic) psychostimulants. In this study we have tested animals from both strains in two behavioral paradigms that are related to schizophrenia, i.e. prepulse inhibition (PPI) and latent inhibition (LI) of fear-potentiated startle (FPS). The results show that while RLA-I rats display good PPI and LI to the context, RHA-Is show an impairment of PPI and no sign of an LI effect, which goes in the direction of the results obtained in schizophrenic patients. Therefore, although further behavioral and psychopharmacological work needs to be done, the present findings and previous studies carried out in our laboratory and others allow us to propose the RHA-I rat strain as a putative genetic rat model of differential schizophrenia-related features., (Copyright © 2016 Elsevier Inc. All rights reserved.)

This study presents the first evaluation of the associations between responses in two paradigms related to schizophrenia in the genetically heterogeneous NIH-HS rat stock. NIH-HS rats are a stock of genetically heterogeneous animals that have been derived from eight different inbred strains. A rotational breeding schedule has been followed for more than eighty generations, leading to a high level of genetic recombination that makes the NIH-HS rats a unique tool for studying the genetic basis of (biological, behavioral, disease-related) complex traits. Previous work has dealt with the characterization of coping styles, cognitive and anxiety/fear-related profiles of NIH-HS rats. In the present study we have completed their characterization in two behavioral models, prepulse inhibition (PPI) and latent inhibition (LI) of the two-way active avoidance response, that appear to be related to schizophrenia or to schizophrenia-relevant symptoms. We have found that these rats display PPI for each of the four prepulse intensities tested, allowing their stratification in high, medium and low PPI subgroups. When testing these three subgroups for LI of two-way active avoidance acquisition it has been observed that the LowPPI and MediumPPI subgroups present impaired LI, which, along with the fact that the HighPPI group presents significant LI, allows us to hypothesize that responses in these two paradigms are somehow related and that selection of NIH-HS rats for Low vs HighPPI could make a promising animal model for the study of clusters of schizophrenia-relevant symptoms and their underlying neurobiological mechanisms., (Copyright © 2015 Elsevier Inc. All rights reserved.)