Substance use disorder (SUD) affects 8.5% of the United States population with many individuals who go
through cycles of abstinence and then relapse to drug taking. Stress is one of many factors that can potentiate
drug relapse and a key neural circuit involved in stress-potentiated drug seeking behavior involves neurons in
the prefrontal cortex (PFC) that project to the nucleus accumbens (NAc). Emerging evidence has shown that
CORT can regulate the endocannabinoid signaling system in a rapid and glucocorticoid receptor independent
manner. Previous studies from our group indicate that CORT rapidly mobilizes 2-arachidonoylglycerol (2-AG)
in medial prefrontal cortex (mPFC) pyramidal neurons which activates cannabinoid 1 receptors (CB1Rs) on
GABAergic axons to inhibit GABA release in a retrograde manner. We hypothesize that this effect of CORT
decreases inhibitory synaptic transmission, thus increasing excitability of neurons in the mPFC that comprise
output pathways that mediate motivation and promote cocaine seeking in abstinent rats. However, the precise
mechanism through which CORT rapidly mobilizes 2-AG is unclear. The purpose of this research project is to
examine the overall hypothesis that Gq-coupled GPCR signaling is required for the rapid CORT
mobilization of 2-AG in the PFC and that this mechanism underlies CORT-dependent effects of stress-
potentiated relapse in substance use disorder. To test this hypothesis, I will utilize ex vivo whole cell
recordings, a self-administration/cocaine seeking paradigm, an eCBGRAB2.0 approach, and fiber photometry. In
Aim 1, I will conduct ex vivo whole cell recordings of PFC pyramidal neurons to assess GABAergic
neurotransmission and photometry in brain slices following eCBGRAB2.0 expression to directly measure 2-AG
release to examine the mechanism by which CORT recruits endocannabinoid signaling at this synapse. I will
examine the requirement for CORT induced Gq-mediated signaling to increase 2-AG synthesis. In Aim 2, I will
study rats in a self-administration/cocaine seeking paradigm alongside fiber photometry following the
expression of an eCBGRAB2.0 biosensor to study endocannabinoid concentrations within the mPFC during
CORT-potentiated reinstatement of drug seeking. Successful completion of these aims will enhance our
understanding of the mechanism by which CORT mobilizes endocannabinoid signaling and increase our ability
to design therapeutic interventions towards SUDs. The associated fellowship training plan aligns with these
research aims and leverages my development as a research scientist and interactions with my mentorship
team to enhance my technical, intellectual, and professional development to support my goal of becoming an
independent investigator working in an academic environment. The environment in the Department of
Pharmacology at the Medical College of Wisconsin has high-quality instrumentation for the proposed studies
and provides supportive faculty towards my future goals to obtain my PhD and become an independent
researcher.