Impact of vaporized nicotine and cannabis co-exposure in adolescence on sex-specific behavioural and neural effects in adulthood
Abstract
Nicotine and cannabis are commonly co-used during adolescence, yet there is limited research on their long-lasting impacts on behavior and neural connectivity. This study examines the long-term effects of adolescent exposure to nicotine and high Δ9-tetrahydrocannabinol-cannabis (THC) flower vapor on brain development and reward-learning and seeking behavior. Male and female adolescent Sprague-Dawley rats received daily exposure to vaporized nicotine, THC, both nicotine and THC together, or vehicle vapor. In adulthood, behavioral tests and MRI scans were conducted. Female adult rats co-exposed to both nicotine and THC in adolescence demonstrated a heightened sensitivity to reward, while males exposed to THC displayed learning impairments. Males exposed to THC also expressed one network with increased functional connectivity compared to the co-exposed nicotine and THC group. Our results indicate that co-exposure to vaporized cannabis and nicotine during adolescence produces long-term sex-specific effects in reward- and cognition-related behavior.