Locomotor sensitization and anxiety-like behavior in rats exposed to electronic cigarette aerosol or smoke

Abstract The increasing prevalence of e-cigarette use, particularly among adolescents, raises critical questions about the neurobehavioral impact of nicotine delivery via vapor compared to traditional cigarette smoke. While both contain nicotine, their differing chemical compositions may lead to divergent effects on locomotor function and anxiety-related behavior.Methods. Male Wistar rats were exposed for six weeks to either cigarette smoke, e-cigarette vapor (12 mg/ml nicotine), or filtered air (control) using a standardized puffing protocol. Behavioral assessments included the Open Field Test and Elevated Plus Maze to evaluate locomotor activity and anxiety-like behavior. Quantitative analyses encompassed parameters such as total distance traveled, thigmotaxis, rearing (wall-supported and freestanding), immobility, grooming, and exploration of open/closed arms.Results. Cigarette smoke exposure significantly increased locomotor activity and exploratory behavior, with a predominance of freestanding rearing and prolonged presence in anxiogenic environments (open arms and central zones), indicating a possible anxiolytic effect. In contrast, e-cigarette vapor exposure induced behavioral signs of heightened anxiety, including increased thigmotaxis and reduced central zone exploration.Conclusions:Despite delivering comparable nicotine doses, cigarette smoke and e-cigarette vapor produce markedly different neurobehavioral outcomes. Cigarette smoke appears to exert anxiolytic and locomotor-sensitizing effects, whereas vapor exposure may dysregulate anxiety pathways without reinforcing locomotor activation. These findings underscore the need to re-evaluate the assumed safety of e-cigarettes, especially in young populations.