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Sex differences in social interaction behavior following social defeat stress in the monogamous California mouse (Peromyscus californicus).

Trainor BC, Pride MC, Villalon Landeros R, Knoblauch NW, Takahashi EY, Silva AL, Crean KK - PLoS ONE (2011)

Bottom Line: Social defeat reduced social interaction responses in females but not males.This effect of defeat was not observed in males.The effects of defeat in females were limited to social contexts, as there were no differences in exploratory behavior in the open field or light-dark box test.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of California Davis, Davis, California, United States of America. bctrainor@ucdavis.edu

ABSTRACT
Stressful life experiences are known to be a precipitating factor for many mental disorders. The social defeat model induces behavioral responses in rodents (e.g. reduced social interaction) that are similar to behavioral patterns associated with mood disorders. The model has contributed to the discovery of novel mechanisms regulating behavioral responses to stress, but its utility has been largely limited to males. This is disadvantageous because most mood disorders have a higher incidence in women versus men. Male and female California mice (Peromyscus californicus) aggressively defend territories, which allowed us to observe the effects of social defeat in both sexes. In two experiments, mice were exposed to three social defeat or control episodes. Mice were then behaviorally phenotyped, and indirect markers of brain activity and corticosterone responses to a novel social stimulus were assessed. Sex differences in behavioral responses to social stress were long lasting (4 wks). Social defeat reduced social interaction responses in females but not males. In females, social defeat induced an increase in the number of phosphorylated CREB positive cells in the nucleus accumbens shell after exposure to a novel social stimulus. This effect of defeat was not observed in males. The effects of defeat in females were limited to social contexts, as there were no differences in exploratory behavior in the open field or light-dark box test. These data suggest that California mice could be a useful model for studying sex differences in behavioral responses to stress, particularly in neurobiological mechanisms that are involved with the regulation of social behavior.

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Effects of social defeat in the habituation-dishabituation test.Social defeat reduced time spent investigating a glass slide with a water droplet (trials 1–3) in both males (A) and females (B). In males defeat reduced, but did not eliminate investigation of novel male odors (trial 4 and 7). Females exposed to defeat did not show a significant increase in investigation time of novel female odors (trials 4 and 7). †, †† Mann-Whitney effect of stress p<0.05 and p<0.01 respectively. *, ** Wilcoxon test versus previous trial (trial 3 vs. 4 or 6 vs. 7) p<0.05, p<0.01 respectively. All data are mean±s.e.
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pone-0017405-g007: Effects of social defeat in the habituation-dishabituation test.Social defeat reduced time spent investigating a glass slide with a water droplet (trials 1–3) in both males (A) and females (B). In males defeat reduced, but did not eliminate investigation of novel male odors (trial 4 and 7). Females exposed to defeat did not show a significant increase in investigation time of novel female odors (trials 4 and 7). †, †† Mann-Whitney effect of stress p<0.05 and p<0.01 respectively. *, ** Wilcoxon test versus previous trial (trial 3 vs. 4 or 6 vs. 7) p<0.05, p<0.01 respectively. All data are mean±s.e.

Mentions: In habituation-dishabituation tests, both control and stressed males (Fig. 7a) showed a significant increase in time spent investigating urine from unfamiliar males. In contrast, only control females showed a significant increase in time spent investigating urine from unfamiliar females whereas stressed females did not (Fig. 7b). Social defeat, reduced the amount of time both males and females investigated both social and non social odors (water controls), suggesting that social defeat may induce an aversion to novel objects within the home cage.


Sex differences in social interaction behavior following social defeat stress in the monogamous California mouse (Peromyscus californicus).

Trainor BC, Pride MC, Villalon Landeros R, Knoblauch NW, Takahashi EY, Silva AL, Crean KK - PLoS ONE (2011)

Effects of social defeat in the habituation-dishabituation test.Social defeat reduced time spent investigating a glass slide with a water droplet (trials 1–3) in both males (A) and females (B). In males defeat reduced, but did not eliminate investigation of novel male odors (trial 4 and 7). Females exposed to defeat did not show a significant increase in investigation time of novel female odors (trials 4 and 7). †, †† Mann-Whitney effect of stress p<0.05 and p<0.01 respectively. *, ** Wilcoxon test versus previous trial (trial 3 vs. 4 or 6 vs. 7) p<0.05, p<0.01 respectively. All data are mean±s.e.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3045459&req=5

pone-0017405-g007: Effects of social defeat in the habituation-dishabituation test.Social defeat reduced time spent investigating a glass slide with a water droplet (trials 1–3) in both males (A) and females (B). In males defeat reduced, but did not eliminate investigation of novel male odors (trial 4 and 7). Females exposed to defeat did not show a significant increase in investigation time of novel female odors (trials 4 and 7). †, †† Mann-Whitney effect of stress p<0.05 and p<0.01 respectively. *, ** Wilcoxon test versus previous trial (trial 3 vs. 4 or 6 vs. 7) p<0.05, p<0.01 respectively. All data are mean±s.e.
Mentions: In habituation-dishabituation tests, both control and stressed males (Fig. 7a) showed a significant increase in time spent investigating urine from unfamiliar males. In contrast, only control females showed a significant increase in time spent investigating urine from unfamiliar females whereas stressed females did not (Fig. 7b). Social defeat, reduced the amount of time both males and females investigated both social and non social odors (water controls), suggesting that social defeat may induce an aversion to novel objects within the home cage.

Bottom Line: Social defeat reduced social interaction responses in females but not males.This effect of defeat was not observed in males.The effects of defeat in females were limited to social contexts, as there were no differences in exploratory behavior in the open field or light-dark box test.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of California Davis, Davis, California, United States of America. bctrainor@ucdavis.edu

ABSTRACT
Stressful life experiences are known to be a precipitating factor for many mental disorders. The social defeat model induces behavioral responses in rodents (e.g. reduced social interaction) that are similar to behavioral patterns associated with mood disorders. The model has contributed to the discovery of novel mechanisms regulating behavioral responses to stress, but its utility has been largely limited to males. This is disadvantageous because most mood disorders have a higher incidence in women versus men. Male and female California mice (Peromyscus californicus) aggressively defend territories, which allowed us to observe the effects of social defeat in both sexes. In two experiments, mice were exposed to three social defeat or control episodes. Mice were then behaviorally phenotyped, and indirect markers of brain activity and corticosterone responses to a novel social stimulus were assessed. Sex differences in behavioral responses to social stress were long lasting (4 wks). Social defeat reduced social interaction responses in females but not males. In females, social defeat induced an increase in the number of phosphorylated CREB positive cells in the nucleus accumbens shell after exposure to a novel social stimulus. This effect of defeat was not observed in males. The effects of defeat in females were limited to social contexts, as there were no differences in exploratory behavior in the open field or light-dark box test. These data suggest that California mice could be a useful model for studying sex differences in behavioral responses to stress, particularly in neurobiological mechanisms that are involved with the regulation of social behavior.

Show MeSH
Related in: MedlinePlus