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.

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Available from: Gloria Blázquez, Aug 20, 2015
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    • "This hypothesis is not incompatible with previous data, and two different kinds of evidence could indirectly support it, First, in the inbred Roman rat (i.e. RHA-I and RLA-I) strains, which have been psychogeneticallyselected for their extreme responses in anxiety-related tasks, the low anxious (and high impulsive) RHA-I strain do not show fear-induced potentiation of startle in a typical cue-conditioning procedure, while the relatively high anxious (and low impulsive) RLA-I strain show clear fear-potentiated startle responses [12]. Second, some seminal conditioning studies in psychopaths using single cue paradigms and electrodermal activity showed less conditioning in these subjects compared with control participants [16] [17], and recent studies have also shown that psychopathic and antisocial individuals do not show increased skin conductance responses to CS+ stimuli in differential conditioning paradigms [18] [19]. "
    Open Journal of Psychiatry 01/2013; 3(02):230-7. DOI:10.4236/ojpsych.2013.32021
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    • "RLA < RHA and RLA-I < RHA-I [11] [13] [41] EPHX2 * Saccharin preference RLA < RHA [16] [37] EPHX2 * Stress-induced prolactin response RLA > RHA RLA-I > RHA-I [18,41,42] [7] [9] PRL * Passive coping responses (e.g. self-grooming, freezing) under exposure to novelty RLA-I > RHA-I RLA > RHA and RLA-I > RHA-I [13] [41] CAMKK2 * Classical fear conditioning (freezing) and fear-potentiated startle RLA-I > RHA-I [28] [49] CAMMK2 * Stress-induced RLA > RHA [2] [7] [18] [41] [42] [46] CRHBP (CRH-dependent) HPA-axis hormonal responses RLA-I > RHA-I [6] [9] [11] * CRH receptors in hypothalamus and BNST RLA-I > RHA-I [6] CRHBP * Novelty-seeking behavior RHA > RLA RHA-I > RLA-I [16] [13] HOMER3 * Ethanol and cocaine-seeking behavior RHA > RLA [15] [16] [19] [37] HOMER3 * Impulsivity behavior and attention deficits RHA-I > RLA-I [33] "
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    ABSTRACT: Microarray technology was used to explore differences in brain gene expression under basal conditions in two strains of psychogenetically selected rats which differ in anxiety/stress responses, the inbred Roman High-(RHA-I) and Roman Low-(RLA-I) Avoidance rats. Microarray analysis detected 14 up-regulated and 24 down-regulated genes in RLA-I vs. RHA-I rats functionally related to neurobiological processes. The differentially expressed genes CAMKK2, CRHBP, EPHX2, HOMER3, NDN, PRL and RPL6 were selected for microarray validation using qRT-PCR. EPHX2, CAMKK2 (both up-regulated in RLA-I vs. RHA-I rats) and HOMER3 (down-regulated in RLA-I vs. RHA-I rats) showed a similar tendency and fold-change both in microarray and RT-PCR analyses; PRL (up-regulated in RLA-I vs. RHA-I rats), CRHBP and RPL6 (both down-regulated in RLA-I vs. RHA-I animals) showed a similar tendency but a different order of magnitude of change among experiments; finally, NDN was validated neither in tendency nor in magnitude of change.
    Neuroscience Letters 09/2011; 504(3):265-70. DOI:10.1016/j.neulet.2011.09.044 · 2.06 Impact Factor
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    • "The observation of strain differences in the effect of IL lesions on extinction is not surprising in the light of several reports of strain differences in fear-motivated behavior (Balogh & Wehner, 2003; Brinks, de Kloet, & Oitzl, 2008; Capone, Venerosi, Puopolo, Alleva, & Cirulli, 2005; Glowa & Hansen, 1994; Hefner et al., 2008; Lopez-Aumatell et al., 2009; Neophytou et al., 2000; Rex, Sondern, Voigt, Franck, & Fink, 1996; Waddell, Dunnett, & Falls, 2004). There are also many reports of strain differences in the effects of a variety of pharmacological challenges and brain lesions on defensive behaviors (Gerlai, 1998; Hefner et al., 2008; Restivo, Passino, Middei, & Ammassari-Teule, 2002; Solecki, Turek, Kubik, & Przewlocki, 2009). "
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    ABSTRACT: The infralimbic division of the medial prefrontal cortex (IL) has been implicated in the consolidation and retention of extinction memories. However, the effects of IL lesions on the retention of extinction memory are inconsistent. In the present experiments, we examined whether rat strain influences the effects of IL lesions on extinction. In Experiment 1, Sprague-Dawley (SD) or Long-Evans (LE) rats received a standard auditory fear conditioning procedure, which was followed by an extinction session; freezing served as the index of conditional fear. Our results reveal that focal IL lesions impair the retention of extinction in SD, but not LE rats. In addition to the strain difference in sensitivity to IL lesions, LE rats exhibited significantly higher levels of contextual fear before the outset of extinction training than SD rats. In a second experiment we thus examined whether contextual fear influenced the sensitivity of extinction to IL lesions in LE rats. LE rats received the same conditioning as in Experiment 1, and then were either merely exposed to a novel context or administered unsignaled shocks in that context, followed by extinction and test sessions. Our results reveal that LE rats with IL lesions showed normal extinction regardless of the levels of contextual fear manifest before extinction. Thus, we conclude that rat strain is an important variable that influences the role of infralimbic cortex in fear extinction.
    Behavioral Neuroscience 06/2010; 124(3):391-7. DOI:10.1037/a0019479 · 3.25 Impact Factor
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