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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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Representation of areas quantified using microscopic analyses in experiment 1.Reproduced from Paxinos & Franklin (2003), with permission from Academic Press. Abbreviations: Nucleus accumbens (NAc), dorsomedial bed nucleus of the stria terminalis (dmBNST), dorsolateral bed nucleus of the stria terminalis (dlBNST), ventral bed nucleus of the stria terminalis (vBNST), paraventricular nucleus (PVN), basolateral amygdala (BLA), central nucleus of the amygdala (CEA), dorsomedial amygdala (dMEA), dorsoventral amygdala (vMEA).
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pone-0017405-g002: Representation of areas quantified using microscopic analyses in experiment 1.Reproduced from Paxinos & Franklin (2003), with permission from Academic Press. Abbreviations: Nucleus accumbens (NAc), dorsomedial bed nucleus of the stria terminalis (dmBNST), dorsolateral bed nucleus of the stria terminalis (dlBNST), ventral bed nucleus of the stria terminalis (vBNST), paraventricular nucleus (PVN), basolateral amygdala (BLA), central nucleus of the amygdala (CEA), dorsomedial amygdala (dMEA), dorsoventral amygdala (vMEA).

Mentions: Representative photomicrographs (Fig. 2) were taken with a Zeiss AxioImager and were based on a mouse brain atlas [40]. The background for each image was normalized by adjusting the exposure time. The number of immunopositive cells in each brain area was counted in a frame of uniform size (NAc core, 0.3×0.29 mm; NAc shell, 0.3×0.29 mm; dorsomedial BNST, 0.53×0.3 mm; dorsolateral BNST, 0.53×0.33 mm; ventral BNST, 0.34×0.34 mm; PVN 0.24×0.18 mm; dorsal MEA, 0.33×0.38 mm; ventral MEA, 0.33×0.38 mm; BLA, 0.38×0.19 mm; CEA, 0.38 mm diameter circle) using Image J (NIH, Bethesda, MD) by an observer unaware of treatment assignments. The number of positive cells was counted using the “analyze particles” function of Image J. Cell count data are presented as number of positive cells per mm2.


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)

Representation of areas quantified using microscopic analyses in experiment 1.Reproduced from Paxinos & Franklin (2003), with permission from Academic Press. Abbreviations: Nucleus accumbens (NAc), dorsomedial bed nucleus of the stria terminalis (dmBNST), dorsolateral bed nucleus of the stria terminalis (dlBNST), ventral bed nucleus of the stria terminalis (vBNST), paraventricular nucleus (PVN), basolateral amygdala (BLA), central nucleus of the amygdala (CEA), dorsomedial amygdala (dMEA), dorsoventral amygdala (vMEA).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3045459&req=5

pone-0017405-g002: Representation of areas quantified using microscopic analyses in experiment 1.Reproduced from Paxinos & Franklin (2003), with permission from Academic Press. Abbreviations: Nucleus accumbens (NAc), dorsomedial bed nucleus of the stria terminalis (dmBNST), dorsolateral bed nucleus of the stria terminalis (dlBNST), ventral bed nucleus of the stria terminalis (vBNST), paraventricular nucleus (PVN), basolateral amygdala (BLA), central nucleus of the amygdala (CEA), dorsomedial amygdala (dMEA), dorsoventral amygdala (vMEA).
Mentions: Representative photomicrographs (Fig. 2) were taken with a Zeiss AxioImager and were based on a mouse brain atlas [40]. The background for each image was normalized by adjusting the exposure time. The number of immunopositive cells in each brain area was counted in a frame of uniform size (NAc core, 0.3×0.29 mm; NAc shell, 0.3×0.29 mm; dorsomedial BNST, 0.53×0.3 mm; dorsolateral BNST, 0.53×0.33 mm; ventral BNST, 0.34×0.34 mm; PVN 0.24×0.18 mm; dorsal MEA, 0.33×0.38 mm; ventral MEA, 0.33×0.38 mm; BLA, 0.38×0.19 mm; CEA, 0.38 mm diameter circle) using Image J (NIH, Bethesda, MD) by an observer unaware of treatment assignments. The number of positive cells was counted using the “analyze particles” function of Image J. Cell count data are presented as number of positive cells per mm2.

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