Presenter: Rose Maniani

Faculty Sponsor: Lisa Maeng

School: UMass Boston

Research Area: Psychology and Behavioral Sciences

Session: Poster Session 3, 1:15 PM - 2:00 PM, Auditorium, A62

ABSTRACT

The gut microbiome is altered in fear-related psychiatric disorders, which are more prevalent in women. Previous research has shown that manipulating the gut microbiome through probiotic administration such as Lactobacillus rhamnosus (LR) reduces stress responses and anxiety-like behavior in male mice. Despite sex differences in fear-related disorders, no studies have examined sex differences in probiotic effects on fear extinction, the learned inhibition of fear. The activity of GABA, an inhibitory neurotransmitter, in the hippocampus is critical for fear extinction and recall, and estradiol, a sex hormone that enhances extinction memory, can increase GABA. This study investigated how LR impacts neuronal activity (c-Fos) and GAD67, an enzyme critical for GABA synthesis, in hippocampal subregions (dentate gyrus (DG), CA1, and CA3) during extinction recall. 56 adult Sprague Dawley female and male rats received LR or vehicle treatment for 21 days and underwent fear conditioning, extinction, and recall. We hypothesized that there would be better extinction recall and thus greater hippocampal GAD67 and c-Fos expression with LR treatment and in females compared to males. We found that males had less c-Fos in the DG compared to females regardless of treatment [p=0.009], but found no treatment effects. Sex and LR treatment did not influence GAD67 expression, but it was greatest in the CA1 [p<0.001]. These findings suggest that despite not observing behavioral differences, probiotic treatment can alter hippocampal activity in a sex-dependent and region-specific manner and should be further investigated in future studies.