The rodent electronic nicotine delivery system: Apparatus for voluntary nose-only e-cigarette aerosol inhalation

Tobacco use is the leading cause of death globally and in the United States. After decades of decline, driven by decreases in combusted tobacco use, nicotine product use has increased due to electronic nicotine delivery systems, also known as e-cigarettes or vapes. Preclinical models of nicotine self-administration can serve as important lodestars in the search for effective intervention and prevention tactics. Current variants of the preclinical models have substantial limitations, however. Therefore, we created the rodent electronic nicotine delivery system (RENDS), a novel low-cost nonproprietary nose-only preclinical model of nicotine aerosol self-administration. We confirmed that RENDS sequesters nicotine aerosol in the nose port by measuring fine particulate matter (PM <2.5 microns) generated by e-cigarettes. We also showed that rats robustly self-administer flavored nicotine aerosol, resulting in high blood levels of cotinine (the major nicotine metabolite) and spontaneous somatic withdrawal symptoms. Thus, we provide validation of the operation and function of the RENDS, opening the door to an open-source preclinical aerosol model of nicotine self-administration that is relatively low in cost. Four existing operant chambers can be retrofitted with the RENDS for less than $325/chamber. All RENDS diagrams and plans for custom-designed components are on Open Science Framework (https://osf.io/x2pqf/?view_only=775b55435b8e428f98e6da384ef7889d).