Neonatal handling decreases unconditioned anxiety, conditioned fear, and improves two-way avoidance acquisition: a study with the inbred Roman high (RHA-I)- and low-avoidance (RLA-I) rats of both sexes

The present study evaluated the long-lasting effects of neonatal handling (H; administered during the first 21 days of life) on unlearned and learned anxiety-related responses in inbred Roman High- (RHA-I) and Low-avoidance (RLA-I) rats. To this aim, untreated and neonatally-handled RHA-I and RLA-I rats of both sexes were tested in the following tests/tasks in baseline acoustic startle (BAS) test, a context-conditioned fear (CCF) test and the acquisition of two-way active –shuttle box- avoidance (SHAV). RLA-I rats showed higher unconditioned (NOE, ZM, BAS) and conditioned (CCF, SHAV) anxiety. H treatment increased exploration of the novel object in the NOE test as well as exploration of the open sections of the ZM test in both rat strains and sexes, although the effects were relatively more marked in the (high anxious) RLA-I strain and in females. Neonatal handling did not affect BAS, but reduced context-conditioned fear in both strains and sexes, and improved shuttle box avoidance acquisition especially in RLA-I (and particularly in females) and in female RHA-I rats. These are completely novel findings, and may suggest that H-induced changes in hippocampal function, which is enhanced in RLA-Is vs RHA-I rats, could be a candidate mechanism underlying the observed long-lasting benefits of neonatal handling on known hippocampal-dependent responses/tasks

Susceptibility to experimental autoimmune encephalomyelitis (model of multiple sclerosis) and anxiety in genetically heterogeneous rats

Las respuestas al estrés del eje hipotalámico-pituitario-adrenal (HPA) juegan un papel decisivo tanto en la conducta ansiosa como en el funcionamiento del sistema inmune (IS). Es sabido que los niveles elevados de glucocorticoides (GC) desempeñan un papel protector ante la encefalomielitis experimental autoinmune (EAE), fiable modelo animal de la esclerosis múltiple. En esta Tesis, nos propusimos investigar si un determinado perfil ansioso podría corresponderse con un perfil específico de sensibilidad a la inflamación. En el "Estudio I", ratas genéticamente heterogéneas N/Nih-HS de ambos sexos fueron inmunizadas con proteína oligodendrocito de la mielina (MOG) para evaluar la EAE. Con el objetivo de valorar los efectos de la ansiedad sobre el IS, examinamos la incidencia (INC) y la severidad de la EAE que presentaban los subgrupos de ratas con puntuaciones extremas en ansiedad. De estos subgrupos (de baja y alta ansiedad) también se comparó la conducta ansiosa y el peso relativo de las glándulas adrenales (RAW). Los resultados indicaron una posible relación entre alta ansiedad y resistencia a la EAE. Sin embargo, algunas de las asociaciones asumidas en el "Estudio I" entre conducta ansiosa y estrés fisiológico, debían esclarecerse. Para ello, en el "Estudio II" se estudiaron las posibles relaciones entre las respuestas del eje HPA y la ansiedad las ratas inbred DA y PVG de ambos sexos. Las cepas DA y PVG son respectivamente susceptible y resistente a un amplio espectro de enfermedades autoinmunes, entre otras, la EAE. En el presente estudio, se caracterizaron estas cepas por sus conductas de miedo/ansiedad y actividad ante la novedad. Además se examinó la function del eje HPA, en terminos de niveles de corticosterona (basal y post-stress), peso relativo de las glándulas adrenales, y su expresión mRNA del receptor de la hormona adrenocorticotropa (MC2R). También se estudió la expresión mRNA de CD74 (complejo mayor de histocompatibilidad, clase II); y la interleucina proinflamatoria-6 (IL-6), en el núcleo paraventricular del hipotálamo, la pituitaria y las adrenales. En conjunto, nuestros resultados muestran que en la EAE, un perfil ansioso se correspondería con un eje HPA incrementado, que podría actuar reprimiendo las respuestas inflamatorias, produciendo un efecto de cierta resistencia a la EAE.Stress hypothalamic-pituitary-adrenal (HPA) axis responses play a role in both anxiety behaviour and immune system (IS). Enhanced glucocorticoid (GC) levels have shown to play a protective role in experimental autoimmune encephalomyelitis (EAE), a reliable animal model of multiple sclerosis. In this Thesis, we aimed to investigate if a determined anxious profile could correspond to a specific inflammatory susceptibility. In "Study I", genetically heterogeneous N/Nih-HS rats of both sexes were immunized with myelin oligodendrocyte glycoprotein (MOG) to evaluate EAE. To assess the effect of anxiety on IS, subgroups of rats scoring extreme values of anxiety were examined on their EAE incidence (INC) and severity. Also, anxious behaviour and relative adrenal weight (RAW) of subgroups selected by resistance or susceptibility was studied was compared. Results indicated a possible relationship between high anxiety and EAE-resistance. However, the assumed associations between behavioural anxiety and physiological stress needed to be elucidated. Thus, in "Study II" we studied in male and female DA and PVG inbred rats the possible relationships among HPA axis responses and anxiety. DA and PVG strains are respectively susceptible and resistant to a wide range of experimental autoimmune diseases, EAE among others. In the current study, these strains were characterized by their anxiety/inhibition. We further examined their HPA axis function, by means of (basal and post-stress) corticosterone levels, RAW, and via RT-PCR their expression of mRNA adrenocorticotropin receptor (Melanocortin 2 Receptor, MC2R) on adrenal glands. We also studied the mRNA expression of both CD74 (major histocompatibility complex; MHC-II) and the pro-inflammatory interleukin-6 (IL-6) on paraventricular nucleus of the hypothalamus (PVN), pituitary and adrenal glands. Together, our data show that in EAE, a high anxious profile accompanied by an enhanced HPA axis may involve the repression of inflammatory responses, providing a certain resistance

Psychometric Properties of the Clinical Assessment of Prosocial Emotions Version 1.1 (CAPE 1.1) in Young Males Who Were Incarcerated

This research was financially supported by the Centre d'Estudis Jurídics i Formació Especialitzada, Generalitat de Catalunya (DOGC Núm. 7024-23.12.05; DOGC Núm. 7274 - 27/12/16)The Clinical Assessment of Prosocial Emotions: Version 1.1 (CAPE 1.1) uses structured clinical judgments to diagnose the "with limited prosocial emotions" specifier for Conduct Disorder. This study examined (a) the internal consistency and interrater agreement, and (b) the convergent and divergent validity of the CAPE 1.1 in 72 young males who were incarcerated in two Spanish juvenile detention centers (age range = 14-22 years). The CAPE 1.1 showed good interrater agreement for making the diagnosis of the specifier and adequate internal consistency. The CAPE 1.1 was associated with other measures of callous-unemotional traits, but less consistently associated with other dimensions of psychopathy. Youth who met diagnostic criteria for the specifier scored higher on externalizing problems, but did not differ from other youth who were incarcerated on internalizing problems. These results provide preliminary support for the psychometric properties of the CAPE 1.1 for the clinical assessment of the specifier

Effects of environmental and physiological covariates on sex differences in unconditioned and conditioned anxiety and fear in a large sample of genetically heterogeneous (N/Nih-HS) rats

Physiological and environmental variables, or covariates, can account for an important portion of the variability observed in behavioural/physiological results from different laboratories even when using the same type of animals and phenotyping procedures. We present the results of a behavioural study with a sample of 1456 genetically heterogeneous N/Nih-HS rats, including males and females, which are part of a larger genome-wide fine-mapping QTL (Quantitative Trait Loci) study. N/Nih-HS rats have been derived from 8 inbred strains and provide very small distance between genetic recombinations, which makes them a unique tool for fine-mapping QTL studies. The behavioural test battery comprised the elevated zero-maze test for anxiety, novel-cage (open-field like) activity, two-way active avoidance acquisition (related to conditioned anxiety) and context-conditioned freezing (i.e. classically conditioned fear). Using factorial analyses of variance (ANOVAs) we aimed to analyse sex differences in anxiety and fear in this N/Nih-HS rat sample, as well as to assess the effects of (and interactions with) other independent factors, such as batch, season, coat colour and experimenter. Body weight was taken as a quantitative covariate and analysed by covariance analysis (ANCOVA). Obliquely-rotated factor analyses were also performed separately for each sex, in order to evaluate associations among the most relevant variables from each behavioural test and the common dimensions (i.e. factors) underlying the different behavioural responses. ANOVA analyses showed a consistent pattern of sex effects, with females showing less signs of anxiety and fear than males across all tests. There were also significant main effects of batch, season, colour and experimenter on almost all behavioural variables, as well as "sex × batch", "sex × season" and "sex × experimenter" interactions. Body weight showed significant effects in the ANCOVAs of most behavioural measures, but sex effects were still present in spite of (and after controlling for) these "body weight" effects. Factor analyses of relevant variables from each test showed a two-fold factor structure in both sexes, with the first factor mainly representing anxiety and conditioned fear in males, while in females the first factor was dominated by loadings of activity measures. Thus, besides showing consistent sex differences in anxiety-, fear- and activity-related responses in N/Nih-HS rats, the present study shows that females' behaviour is predominantly influenced by activity while males are more influenced by anxiety. Moreover, the results point out that, besides "sex" effects, physiological variables such as colour and body weight, and environmental factors as batch/season or "experimenter", have to be taken into account in both behavioural and quantitative genetic studies because of their demonstrated influences on phenotypic outcomes

High-resolution genome screen for bone mineral density in heterogeneous stock rat

We previously demonstrated that skeletal mass, structure, and biomechanical properties vary considerably in heterogeneous stock (HS) rat strains. In addition, we observed strong heritability for several of these skeletal phenotypes in the HS rat model, suggesting that it represents a unique genetic resource for dissecting the complex genetics underlying bone fragility. The purpose of this study was to identify and localize genes associated with bone mineral density in HS rats. We measured bone phenotypes from 1524 adult male and female HS rats between 17 and 20 weeks of age. Phenotypes included dual-energy X-ray absorptiometry (DXA) measurements for bone mineral content and areal bone mineral density (aBMD) for femur and lumbar spine (L3-L5), and volumetric BMD measurements by CT for the midshaft and distal femur, femur neck, and fifth lumbar vertebra (L5). A total of 70,000 polymorphic single-nucleotide polymorphisms (SNPs) distributed throughout the genome were selected from genotypes obtained from the Affymetrix rat custom SNPs array for the HS rat population. These SNPs spanned the HS rat genome with a mean linkage disequilibrium coefficient between neighboring SNPs of 0.95. Haplotypes were estimated across the entire genome for each rat using a multipoint haplotype reconstruction method, which calculates the probability of descent for each genotyped locus from each of the eight founder HS strains. The haplotypes were tested for association with each bone density phenotype via a mixed model with covariate adjustment. We identified quantitative trait loci (QTLs) for BMD phenotypes on chromosomes 2, 9, 10, and 13 meeting a conservative genomewide empiric significance threshold (false discovery rate [FDR] = 5%; p < 3 × 10(-6)). Importantly, most QTLs were localized to very small genomic regions (1-3 megabases [Mb]), allowing us to identify a narrow set of potential candidate genes including both novel genes and genes previously shown to have roles in skeletal development and homeostasis

Fine mapping of bone structure and strength QTLs in heterogeneous stock rat

We previously demonstrated that skeletal structure and strength phenotypes vary considerably in heterogeneous stock (HS) rats. These phenotypes were found to be strongly heritable, suggesting that the HS rat model represents a unique genetic resource for dissecting the complex genetic etiology underlying bone fragility. The purpose of this study was to identify and localize genes associated with bone structure and strength phenotypes using 1524 adult male and female HS rats between 17 to 20 weeks of age. Structure measures included femur length, neck width, head width; femur and lumbar spine (L3-5) areas obtained by DXA; and cross-sectional areas (CSA) at the midshaft, distal femur and femoral neck, and the 5th lumbar vertebra measured by CT. In addition, measures of strength of the whole femur and femoral neck were obtained. Approximately 70,000 polymorphic SNPs distributed throughout the rat genome were selected for genotyping, with a mean linkage disequilibrium coefficient between neighboring SNPs of 0.95. Haplotypes were estimated across the entire genome for each rat using a multipoint haplotype reconstruction method, which calculates the probability of descent at each locus from each of the 8 HS founder strains. The haplotypes were then tested for association with each structure and strength phenotype via a mixed model with covariate adjustment. We identified quantitative trait loci (QTLs) for structure phenotypes on chromosomes 3, 8, 10, 12, 17 and 20, and QTLs for strength phenotypes on chromosomes 5, 10 and 11 that met a conservative genome-wide empiric significance threshold (FDR=5%; P<3×10(-6)). Importantly, most QTLs were localized to very narrow genomic regions (as small as 0.3 Mb and up to 3 Mb), each harboring a small set of candidate genes, both novel and previously shown to have roles in skeletal development and homeostasis

Aplicabilidad del análisis de microarray en la detección de patrones de expresión genética diferencial en procesos psicológicos: expresión genética amigdalar en ratas N/Nih-HS extremas en ansiedad.

En el presente trabajo, se revisan las principales investigaciones sobre las bases gen&eacute;ticas del miedo, los trastornos de ansiedad y depresivos, as&iacute; como de la susceptibilidad a las drogas, que han utilizado la t&eacute;cnica de microarray. Finalmente se presenta un resumen de algunos resultados preliminares, obtenidos por nuestro grupo de investigaci&oacute;n, en el an&aacute;lisis de la expresi&oacute;n g&eacute;nica diferencial en ratas gen&eacute;ticamente heterog&eacute;neas (N/Nih-HS) seleccionadas por su alta/baja ansiedad, en funci&oacute;n de su capacidad para la adquisici&oacute;n de la tarea de evitaci&oacute;n activa en dos sentidos (en la Shuttle-box)

Ansiedad en ratas genéticamente heterogéneas : hacia la identificación de genes para caracteres conductuales cuantitativos

El uso de roedores genéticamente heterogéneos constituye una estrategia única para la identificación y el 'mapeo fino' a alta resolución de locus genéticos (QTL) con influencia sobre fenotipos cuantitativos biológicos y conductuales, permitiendo la identificación de genes individuales (genes cuantitativos) con acción sobre aquéllos. Presentamos el primer estudio de este tipo con ratas genéticamente heterogéneas (N/Nih-HS; derivadas de ocho cepas de ratas consanguíneas), que se evalúan en varias pruebas conductuales que miden ansiedad/miedo no aprendidos ('Caja blanca/negra', 'Laberinto en 'cero' elevado') o aprendidos (conducta de petrificación en contexto condicionado, adquisición de la evitación activa en dos sentidos en la caja de vaivén). Las ratas N/Nih-HS presentan una conducta más parecida a la de la cepa consanguínea RLA-I (ansiosas) que a la de la RHA-I (poco ansiosas). Se hallan correlaciones significativas entre variables incondicionadas de ansiedad y de la adquisición de la evitación activa en dos sentidos, confirmadas parcialmente por análisis de regresión múltiple. Las ratas N/Nih-HS relativamente 'evitadoras' exhiben niveles más bajos de ansiedad no aprendida que las poco 'evitadoras'. Los resultados de esta evaluación del comportamiento de las ratas N/Nih-HS son discutidos en términos de su potencial utilidad para la investigación neurogenética de la ansiedad y el miedoThe use of genetically heterogeneous (outbred) rodents is a unique resource for the identification and fine mapping of genetic loci (QTL) influencing biological and behavioural quantitative phenotypes, allowing the identification of quantitative genes. We present the first study of this kind carried out with genetically heterogeneous rats (N/Nih-HS; derivated from an eight-way cross of inbred strains), whose behaviour is assessed in tests evoking unlearned (Black/white box, Elevated 'zero' maze) or learned (context conditioned freezing, two-way active avoidance acquisition in the shuttlebox) anxious/fearful responses. The behavioural profile of N/Nih-HS rats is more similar to that of RLA-I (anxious) rats rather than to RHA-I (low anxious) rats. Significant correlations are found among unconditioned anxiety variables and two-way active avoidance acquisition in the shuttlebox; these are partially confirmed by multiple regression analysis. 'High avoider' N/Nih-HS rats show lower unlearned anxiety levels than 'low avoiders'. Results of this behavioural assessment of the N/Nih-HS rats are discussed in terms of their potential usefulness for present and future neurobehavioural and genetic studies of fearfulness and anxiet