Summary
Introduction:
This article published in Behavioural Pharmacology reports a study on the behavioral and physiological effects of repeated nicotine vapor inhalation in male and female mice. The study aims to evaluate nicotine vapor inhalation using a model of behavioral sensitization, with intraperitoneal (i.p.) administration of nicotine serving as a positive control, and to determine if there are sex differences for either route of nicotine administration.
Key Points:
* The study used C57BL/6 mice, with 60 males and 64 females, either purchased from Charles River Laboratories or bred at Weber State University.
* Mice were administered vaporized nicotine (0-10.0 mg/ml) or the positive control of i.p. administered nicotine (0.5 mg/kg) once daily for 5 days.
* Behavioral sensitization was measured by assessing locomotor activity, and body temperature was measured before and after nicotine vapor inhalation.
* Nicotine vapor inhalation (1.0-3.0 mg/ml) produced a dose-dependent behavioral sensitization effect and produced hypothermia in male and female mice.
* No sex differences were found for nicotine behavioral sensitization with either route of administration.
* Pretreatment with the nonselective nicotinic antagonist mecamylamine blocked the behavioral sensitization produced by 1.0 mg/ml of nicotine vapor inhalation.
* The methods used in the present study provide an additional behavioral approach for evaluating the behavioral effects of repeated nicotine vapor inhalation that allows the manipulation of several variables, including e-liquid oil blend, e-liquid flavors, puff duration, etc.
Main Message:
The study establishes that nicotine vapor inhalation produces behavioral sensitization in an inverted U-shaped curve that is similar to the effects of injected nicotine across several behavioral models. The results suggest that nicotinic receptor activation is responsible for the behavioral sensitization produced by nicotine vapor inhalation and is not a conditioned response to the vapor. The development of appropriate rodent models is critical for nicotine vapor inhalation research, and the study highlights the importance of considering sex differences in preclinical research. The findings have implications for understanding the behavioral effects of electronic cigarette use and the potential risks associated with their long-term use.
Citation
honeycutt L, huerne K, Miller a, et al. a systematic review of the effects of e-cigarette use on lung function. NPJ primary care respiratory medicine. 2022;32(1):45. doi:10.1038/s41533-022-00311-w
