The Roman High- and Low-Avoidance rat strains differ in fear-potentiated startle and classical aversive conditioning

Psicothema, ISSN 0214-9915, Vol. 21, Nº. 1, 2009, pags. 27-32
Source: OAI

ABSTRACT Las cepas de ratas Roman de alta y baja evitación difieren en respuesta de sobresalto potenciada por miedo y en condicionamiento clásico aversivo. Las sublíneas suizas de ratas Romanas «High»- (RHA/Verh) y «Low»-(RLA/Verh) «Avoidance» han sido seleccionadas genéticamente, desde 1972, en función de su excelente (RHA) o extremadamente pobre adquisición de la tarea de evitación activa en dos sentidos. Cepas consanguíneas (RHA-I y RLA-I), derivadas de las dos líneas anteriores, se mantienen en nuestro laboratorio desde 1997. En comparación con la cepa RHA-I, la cepa RLA-I muestra incrementos en las respuestas hormonales al estrés, así como en conductas de ansiedad/miedo en una variedad de pruebas y variables conductuales incondicionadas. Hasta la fecha, las cepas de ratas Romanas no han sido comparadas en procedimientos de condicionamiento clásico de miedo a contextos o estímulos discretos. El presente trabajo tuvo como objetivo comparar ambas en 1) dos procedimientos de medida de la respuesta de sobresalto potenciada por miedo; y, 2) en un procedimiento de condicionamiento clásico de miedo (petrificación condicionada). Los resultados indican que las ratas RLA-I muestran niveles mayores de condicionamiento de miedo (respuesta de sobresalto y respuesta de petrificación) que las RHA-I, reforzando así los perfiles diferenciales de ansiedad/miedo de las dos cepas.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Grooming occurs during/after stress and seems to accompany dearousal. Here, grooming was investigated under testing situations involving different levels of aversiveness, taking advantage of differences among three rat strains in fearfulness/anxiety. Inbred Roman High Avoidance (RHA-I) rats are less anxious/fearful than inbred Roman Low Avoidance (RLA-I). The outbred genetically heterogeneous stock of rats (NIH-HS), which resembles the RLA-I in many behavioral traits, was also studied. Adult male rats (RLA-I: n=9, RHA-I: n=10, NIH-HS: n=12) were observed for 30min in: a novel open-field, a novel hole-board and in the home-cage. They were also observed during two-way active avoidance training. Differences in grooming depended on test situation: (a) No differences were found in the home-cage. (b) While tested in a novel environment, RHA-I showed less grooming activity than the other rats. (c) After avoidance responses appeared, differences among the strains were opposite to the observed in novelty tests. Furthermore, results suggest that (i) grooming is mostly suppressed when assured aversive experience is under way; (ii) rostral grooming prevails when experience with aversive stimuli is unpredictable (novelty) or potential (avoidance training); (iii) body grooming increases for a period in novel environments. In general, our results support that grooming takes place during dearousal.
    Neuroscience Research 10/2013; · 2.15 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Two recent microarray and qRT-PCR studies showed that inbred Roman High- (RHA-I, low anxiety and frustration vulnerability) and Low-Avoidance (RLA-I, high anxiety and frustration vulnerability) rats, psychogenetically selected on the basis of their divergence in two-way avoidance performance, differed in basal whole-brain and hippocampal expression of genes related to neurotransmission, emotion, stress, aversive learning, and drug seeking behavior. We have extended these studies by analyzing strain differences in hippocampal gene expression following a frustrative experience involving reward downshift, i.e. instrumental successive negative contrast (iSNC), a phenomenon in which the sudden reduction of an expected reward induces frustration/anxiety. Food-deprived male Roman rats were exposed to a reduction in the amount of solid food presented in the goal of a straight alley (from 12 pellets in "training" trials-i.e. preshift trials- to 2 pellets in "frustration testing" trials-i.e. postshift trials-). The iSNC effect, as measured by response latencies in the "postshift" trials, appeared only in RLA- I rats (i.e. higher response latencies in the 12-2 RLA-I group as compared to the 2-2 RLA-I control group in postshift trials). Two and a half hours after the "postshift" behavioral test, hippocampi were removed and stored (-80°C) until analysis. Microarray analysis of these hippocampi showed that four differentially-expressed, and qRT-PCR-validated genes (TAAR2, THAP1, PKD2L1, NANOS), have relevance for brain function and behavior, including schizophrenia, depression, anxiety, and drug addiction, thus showing the usefulness of Roman strains as a genetic model for research on the neurogenetic basis of frustration.
    Behavioural brain research 09/2013; · 3.22 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Ethanol can be used to ameliorate negative emotion in anxiety-inducing situations. Two experiments tested whether rats would increase preference for ethanol immediately after anxiogenic sessions of appetitive extinction. It was predicted that preference for ethanol would be greater in inbred Roman low-avoidance rats (RLA-I) than in inbred Roman high-avoidance rats (RHA-I), given previous research demonstrating that the former strain exhibits greater sensitivity to incentive loss. Experiment 1 used a consummatory extinction task (22-to-0% sucrose downshift), whereas Experiment 2 used an instrumental extinction task (12-to-0 pellet downshift). In both experiments, postsession ethanol consumption was higher in RLA-I rats than in RHA-I rats. No strain differences in ethanol preference were found after acquisition sessions or in groups given postsession access to water. Because ethanol is an anti-anxiety drug, the present results suggest that rats are capable of changing their consummatory behavior to correct for an aversive emotional state induced by incentive loss.
    Physiology & Behavior 10/2013; · 3.03 Impact Factor

Full-text (2 Sources)

Available from
May 22, 2014