Use of the light–dark box to compare the anxiety-related behavior of virgin and postpartum female rats

Abstract

Postpartum female rodents are less anxious than diestrous virgins and this difference contributes to dams’ ability to adequately care for pups and defend the nest. Low postpartum anxiety has been observed in many behavioral paradigms but the results of previous studies using the light-dark box have been inconsistent. We here reexamined the usefulness of the light-dark box to assess differences between postpartum and diestrous virgin female rats in anxiety-related behavior. We found a significant effect of reproductive state, such that dams spent more time in the light chamber than did diestrous virgins. This difference required recent physical contact with pups because a four-hour separation from pups reduced dams’ time spent in the light chamber by half, similar to what we previously found for litter-separated dams tested in an elevated plus maze. Lastly, we examined if dams’ low-anxiety behavior in the light-dark box depends on high GABAA receptor activity by inhibiting the receptor at different binding sites using (+)-Bicuculline to target the GABA site, FG-7142 to target the benzodiazepine site, and pentylenetetrazol to target the picrotoxin site. Only pentylenetetrazol was consistently anxiogenic in dams, while having little effect in diestrous virgins. Thus, the light-dark box can be a useful paradigm to study differences between postpartum and diestrous virgin female rats in their anxiety-related behaviors, and this difference is influenced by dams’ recent contact with pups and GABAA receptor neurotransmission particularly affected by activity at the picrotoxin site.

Response to stress inDrosophilais mediated by gender, age and stress paradigm

“…Postpartum and diestrous virgin females differ in their responses dependent upon light intensity and on the strain of rat (Miller et al, 2011). Both the open field arena and Light-Dark Box assays assess innate behaviors not correlated with learning a task or associated with a punishment; these paradigms induce both fear/avoidance as well as exploratory/approach behaviors (Montgomery, 1955).…”

Behavioral, histopathological and biochemical impairments observed in mice envenomed by the scorpion: Hottentota gentili (Pallary, 1924)

“…The movements were recorded for 5 min (Benammi et al, 2014). The time spent in both dark and light compartments allowed a measure of anxiety (Miller et al, 2011). The box was carefully cleaned with 70% ethanol before each animal was introduced.…”

Lactation does not alter the long-term stability of individual differences in behavior of laboratory mice on the elevated plus maze

“…Possibly, in the first trial, motivation to explore the novel situation presented by the maze counteracted to some extent the more fearful response (or reduced curiosity) seen in later trials after the animals had learned the configuration of the maze and their various response options. Alternatively, it might be assumed that the better illumination of the surface of the open arms (70 cd/m 2 ) than of the closed arms (20 cd/m 2 ) might have led to an increased aversion to the former parts of the elevated plus maze across the different trials (Miller et al 2011). Nevertheless, important for the purpose of our study, these changes in the absolute levels in the animals' behavioral responses over time tested on an individual basis were again decoupled from the females' initial reproductive stage along T 1 and T 2 , and from the changes in the females' reproductive state along T 2 and T 3 (Figs.…”