Evaluating the Multiscale Effects of Fentanyl-Induced Dependence and Abstinence within the Mouse Basolateral Amygdala - PROJECT SUMMARY / ABSTRACT The United States is intensely affected by an ongoing opioid crisis. This crisis has garnered national attention and caused the mobilization of national resources to abate the ongoing crisis. In the previous four years, the U.S. has suffered in excess of 300,000 deaths due to overdose (OD). Over 200,000 of these deaths can be directly attributed to fentanyl abuse. Due to the incredible potency, availability and addictive properties, fentanyl related deaths show no signs of decelerating. Due to the persistent dysphoria and anhedonia in abstinence, fentanyl users are at an immense 4-8 times increased risk of overdose after abstinence. This underscores the importance and urgency by which new research needs to interrogate the substrates predisposing relapse. Novel investigative research must be employed to better understand the mechanisms by which fentanyl induces such dependence and what persistent changes may contribute to relapse. The multiscale approach in this proposal aims to comprehensively evaluate the molecular, projection, and behavioral dynamics disrupted as a result of fentanyl dependence and interrogate these dynamics into abstinence. This approach will incorporate virally-mediated strategies, nuclear labeling, and subsequent single- nucleus RNA sequencing to evaluate how fentanyl dependence and abstinence may differentially affect projections in the basolateral amygdala (BLA). This approach allows for an unprecedented observation into the molecular mechanisms by which fentanyl may differentially affect reward-seeking projections versus aversion- inducing projections with single-cell resolution. Next, this proposal will address how fentanyl dependence and abstinence affects rewarding and punishing experiences by combining in vivo imaging with various behaviors. This combination enables a real-time view of the BLA as it differentially modulates independent projections during valenced behaviors, and importantly, enables us to observe how fentanyl dependence may dysregulate this modulation even after abstinence. This will provide molecular resolution into how fentanyl differentially affects specific BLA projections encoding reward-seeking and avoidance behaviors; then aims to capture the dynamics of these specific projections in vivo while animals perform valenced behaviors. This multiscale approach facilitates a comprehensive investigation into the mechanisms underlying how fentanyl dependence may dysregulate positive or negative reinforcement, even after abstinence. This proposal importantly evaluates the signature fentanyl dependence imprints on the limbic system and may provide novel insights into mechanisms predisposing relapse. The National Institute of Drug Abuse has supported innovative approaches to elucidate and ameliorate drug dependence and relapse for over 50 years. With their support, this research will provide a multimodal training plan as well as insights into the neurobiological underpinnings of fentanyl abuse. This will provide comprehensive training and also facilitate the development of new therapies to abate the opioid crisis.
