Short CommunicationSex differences in the single prolonged stress model

- Sex differences in the SPS model of PTSD were examined.
- SPS induces extinction retention deficits in male, but not female, rats.
- SPS enhanced GR expression in female, but not male, rats.
- Female rats are resilient to SPS.
- GR upregulation does not always coincide with extinction deficits in the SPS model.

Post traumatic stress disorder (PTSD) is a debilitating anxiety disorder resulting from traumatic stress exposure. Females are more likely to develop PTSD than males, but neurobiological mechanisms underlying female susceptibility are lacking. This can be addressed by using nonhuman animal models. Single prolonged stress (SPS), a nonhuman animal model of PTSD, results in cued fear extinction retention deficits and hippocampal glucocorticoid receptor (GR) upregulation in male rats. These effects appear linked in the SPS model, as well as in PTSD. However, the effects of SPS on cued fear extinction retention and hippocampal GRs in female rats remain unknown. Thus, we examined sex differences in SPS-induced cued fear extinction retention deficits and hippocampal GR upregulation. SPS induced cued fear extinction retention deficits in male rats but not female rats. SPS enhanced GR levels in the dorsal hippocampus of female rats, but not male rats. SPS had no effects on ventral hippocampal GR levels, but ventral hippocampal GR levels were attenuated in female rats relative to males. These results suggest that female rats are more resilient to the effects of SPS. The results also suggest that GR upregulation and cued fear extinction retention deficits can be dissociated in the SPS model.