Electronic Vaporization of Nicotine Salt or Freebase produces differential effects on metabolism, neuronal activity and behavior in male and female C57BL/6J mice.

Introduction:
This article examines the differential effects of electronic vaporization of nicotine salt and freebase on metabolism, neuronal activity, and behavior in male and female mice. The study exposed mice to passive electronic vaporization of different nicotine formulations and concentrations and measured serum nicotine metabolite levels, brain activity using cFos expression, and anxiety-like and motivated behavior using the novelty suppressed feeding test.

Key Points:

* The 3% freebase nicotine vapor group displayed significantly higher serum nicotine levels than either 1% or 3% nicotine salt formulations.
* Female mice displayed higher serum nicotine and cotinine levels compared to male mice.
* Central amygdala (Cea) activity was significantly elevated in male mice following nicotine vapor exposure, but the increase was not significantly different between nicotine vapor groups.
* Cea activity in female mice was unaffected.
* Increased activity in the ventral tegmental area (VTa) was only observed in female mice exposed to 3% nicotine freebase and specifically in the dopaminergic population.
* anxiety-like behavior in female mice was relatively unaffected by nicotine vapor exposure, however male mice displayed increased anxiety-like behavior and reduced motivation to feed after vapor exposure, specifically in the 3% freebase group.

Main Message:
The study identifies important sex differences in the impact of nicotine formulation and concentration on nicotine metabolism, brain region-specific activity, and anxiety-like behavior, which may have significant relevance for different consequences of vaping in men and women. These findings highlight the need for further research into the sex-specific effects of nicotine vapor exposure and the potential implications for public health.

Echeveste Sanchez M, Zhu M, Magee S, et al. Electronic Vaporization of Nicotine Salt or Freebase produces differential effects on metabolism, neuronal activity and behavior in male and female C57BL/6J mice. addiction neuroscience. 2023;6. doi:10.1016/j.addicn.2023.100082