Projection-defined ventral tegmental area neurons exhibit distinct fentanyl-induced molecular and functional adaptations that differentially support drug-context associations

Sep 29, 2026

Uploaded by Eliana

Synthetic opioids like fentanyl contribute to unprecedented overdose rates, yet the brain-level effects of fentanyl remain insufficiently understood. The ventral tegmental area (VTA) is a key site for fentanyl’s rewarding actions and sends projections to multiple regions, including the nucleus accumbens (NAc) and prefrontal cortex (PFC). This study tests whether projection-defined VTA neurons respond differently to fentanyl independent of cell type. RNA sequencing, fiber photometry, and chemogenetics show fentanyl produces distinct transcriptional and functional adaptations that shape conditioned place preference and drug-context association.

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Abstract

Introduction

bioRxiv preprint doi: [https://doi.org/10.1101/2025.11.26.690827](https://doi.org/10.1101/2025.11.26.690827); this version posted December 1, 2025. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Title Projection-defined ventral tegmental area neurons exhibit distinct fentanyl-induced molecular and functional adaptations that differentially support drug-context associations Authors Annalisa Montemarano 1 , Hajra Sohail 1 , Logan D. Fox 1 , Laura B. Murdaugh 1 , Alexandria E. Ostman1 , Samiksha Pandey 1 , Kyrsten Derr 1 , Megan E. Fox 1,2,3 1. Department of Anesthesiology and Perioperative Medicine, Pennsylvania State University College of Medicine, Hershey PA 2. Department of Neuroscience and Experimental Therapeutics, Pennsylvania State University College of Medicine, Hershey PA 3. Address correspondence to Megan E Fox 500 University Drive C2850, MC \#H187 Hershey, PA 17033 Tel:717-531-0003 x289635 [mfox@psu.edu](mfox@psu.edu) bioRxiv preprint doi: [https://doi.org/10.1101/2025.11.26.690827](https://doi.org/10.1101/2025.11.26.690827); this version posted December 1, 2025. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Abstract Synthetic opioids like fentanyl are contributing to unprecedented overdose rates. Despite the abundance offentanyl in the illicit drug supply, an understanding of fentanyl’s effects on the brain remains lacking. The ventral tegmental area (VTA) is an important site of fentanyl’s rewarding actions in the brain and sends diverse projections to several regions including the nucleus accumbens (NAc) and prefrontal cortex (PFC) . Previous work shows downstream projection target influences baseline properties and opioid-induced neuroadaptations in VTA, but most work has focused on single neurotransmitter-defined cell types. Here , we investigate how projection-defined VTA neurons exhibit different responses to fentanyl independent of cell type. We use RNA sequencing to show that fentanyl induces discordant transcriptional adaptations in VTA neurons that project to NAc vs PFC. We then used fiber photometry and chemogenetics to characterize functional differences infentanyl-related behavior. We found different timescales of activation between VTA-NAc and VTA-PFC during conditioned place preference that support distinct aspects of fentanyl-context association. Together, our data demonstrate that based on projection target alone, VTA neurons can undergo vastly different adaptations in response to fentanyl, providing new insight into VTA encoding of opioid behaviors. bioRxiv preprint doi: [https://doi.org/10.1101/2025.11.26.690827](https://doi.org/10.1101/2025.11.26.690827); this version posted December 1, 2025. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. INTRODUCTION Opioid use disorder (OUD) is a chronic, relapsing condition that impacts millions of individuals. The rate of opioid overdose deaths in the U.S. has dramatically escalated to unprecedented numbers in recent years , primarily due to increased prevalence of potent synthetic opioids like fentanyl [1] . Fentanyl possesses unique pharmacological properties compared to other opioids: its high lipid solubility allows for rapid passage through the blood brain barrier [2], it exhibits unique binding interactions with the mu opioid receptor [3], and distinct receptor selectivity as compared to morphine [4] . Fentanyl exposure is associated with poorer

FAQs

What is the main question this study investigates about fentanyl effects in the brain?

Whether VTA neurons defined by their projection targets show different molecular and functional adaptations to fentanyl, regardless of cell type.

Which experimental methods are used to measure fentanyl-induced changes?

The study uses RNA sequencing to assess transcriptional adaptations and uses fiber photometry and chemogenetics to characterize functional differences during fentanyl-related behavior.

How do VTA-NAc and VTA-PFC neurons differ in functional timing during conditioned place preference?

They show different timescales of activation during conditioned place preference, supporting distinct aspects of fentanyl-context association.

Sep 29, 2026

Uploaded by Eliana