Profiling coping strategies in male and female rats: Potential neurobehavioral markers of increased resilience to depressive symptoms

Abstract

Coping strategies have been associated with differential stress responsivity, perhaps providing a valuable neurobiological marker for susceptibility to the emergence of depressogenic symptoms or vulnerability to other anxiety-related disorders. Rats profiled with a flexible coping phenotype, for example, exhibit increased neurobiological markers of emotional regulation compared to active and passive copers (Bardi et al., 2012; Lambert et al., 2014). In the current study, responses of male and female rats to prediction errors in a spatial foraging task (dry land maze; DLM) were examined after animals were exposed to chronic unpredictable stress (CUS). Brains were processed following the DLM training/assessment for fos-activation patterns and several measures of neuroplasticity in relevant areas. Behavioral responses observed during both the CUS and DLM phases of testing suggested that males and females employ different means of gathering information such as increased ambulatory exploration in males and rear responses in females. Fecal samples collected during baseline and following CUS swim exposure revealed higher corticosterone (CORT) in active copers, whereas flexible copers had higher dehydroepiandrosterone (DHEA) and DHEA/CORT ratios, both indications of enhanced emotional regulation. Focusing on the neural analysis, flexible copers exhibited fewer fos-immunoreactive cells in the basolateral amygdala and a trend toward lower activation in the insula while encountering the prediction error associated with the DLM probe trial. Coping profiles also differentially influenced markers of neuroplasticity; specifically, flexible copers exhibited higher levels nestin-immunoreactivity (ir). Further, less hippocampal glucocorticoid receptor-ir was observed in the flexible copers than the active and passive copers. In sum, flexible coping rats exhibited evidence of emotional resilience as indicated by several neurobiological measures; however, despite increased rates of depression and related symptoms reported in human females, sex effects weren’t as pervasive as coping strategy profiles in the analysis of neurobiological markers employed in the current study.

Early-life stress affects drug abuse susceptibility in adolescent rat model independently of depression vulnerability

“…However, the data show that MS altered the Wistar emotional state resulting in increased exploratory behaviours when compared with the control rats. The Wistar appear to have more flexible coping strategies than the Kyoto, which does not necessarily mean that their response is a more adaptative one 57 , as suggested by both strains similarly conditioning to cocaine at the CPP test.…”

Volumetric spatial behaviour in rats reveals the anisotropic organisation of navigation

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Behavioral Diversity Across Classic Rodent Models Is Sex-Dependent

“…In males, these groups differed in behaviorally in the FST as well as in several physiological measures of stress, such as fecal corticosterone levels and cardiovascular activation (Hawley et al, 2010 ). However, although females could also be separated by passive, active, and variable coping, their classification was not predictive of behavioral differences in measures of diving in the FST, or of rearing and grooming in the Dry Land Maze task (Kent et al, 2017 ).…”