07/22/2025 | Press release | Distributed by Public on 07/22/2025 13:44
A research team from the Department of Pharmacology, Addiction Science, and Toxicology at the University of Tennessee Health Science Center College of Medicine has received a $3.15 million grant from the National Institute on Drug Abuse. Hao Chen, PhD, Brendan Tunstall, PhD, and Dean Kirson, PhD, are collaborating on a study examining how social interactions can shape the brain's response to nicotine, particularly during adolescence.
Nicotine is known for its addictive properties and is linked to over 480,000 deaths in the United States each year. Despite its unpleasant effects during initial use, many adolescents still begin smoking. Researchers believe that peer influence plays a major role in overriding those negative first experiences. To explore this, Dr. Chen's lab developed a novel research model using adolescent rats to better understand how peer behavior affects nicotine use.
In this model, called Socially Acquired Nicotine Self-Administration (SANSA), adolescent rats are trained to lick a sensor that gives them both a flavored cue and a small dose of nicotine. When tested alone or with a peer who does not get the flavor, the rats typically avoid it, suggesting they find the experience unpleasant. But if they are with a peer who is also consuming the flavor, they continue the behavior, showing that social learning can override the negative experience.
"This model gives us powerful insight into how social environments influence addiction," Dr. Chen said. "It mirrors the human experience, where peer behavior can normalize or even encourage risky behavior like smoking."
Together, the team will now investigate the brain mechanisms behind this effect, focusing on two specific molecular pathways that are believed to be involved in social learning and addiction. One involves the Cacna1c gene, which is linked to smoking initiation in humans and plays a role in neurotransmission. The other is the oxytocin receptor, part of the system that governs social bonding and behavior.
Using advanced tools such as transgenic rats, optogenetics (to control brain activity with light), and real-time brain activity tracking, the team will explore how these pathways interact in a key area of the brain known as the central amygdala, which is involved in emotional processing.
Findings from this work could significantly improve our understanding of how social settings influence substance use and potentially lead to more effective strategies for prevention and treatment, especially among adolescents. "This research could pave the way for new interventions that target social and emotional processes to reduce the risk of addiction," Dr. Tunstall said.