OpenVape: An Open-Source E-Cigarette Vapor Exposure Device for Rodents

Abstract

The prevalence of "vaping" has recently seen significant increases in North America, especially in adolescents. However, the behavioral correlates of vaping are largely unexplored. The uptake of existing technologies meant for rodent vapor inhalation remains limited because of a lack of affordability and versatility (ability to be used with a variety of vaporizers). The OpenVape (OV) offers an open-source, low-cost solution that can be used in a variety of research contexts. Here, we present a specific use case, combining the OV apparatus with JUUL e-cigarettes. This apparatus consists of Arduino-operated vacuum pumps that deliver vapor directly from e-cigarettes to exposure chambers. The OV is easy to build and customize for any type of vaporizer (e.g., nicotine pod or tank; cannabis flower or concentrates). To test the OV, we performed biochemical verification and behavioral studies. The behavioral test (conditioned place preference, CPP) was conducted using adolescent and adult animals to assess developmental differences in the rewarding effects of nicotine vapor, as previously observed with injected nicotine. These findings demonstrate that even after brief exposures to nicotine vapor, pharmacologically relevant nicotine and cotinine levels could be detected in plasma, and significant CPP was observed, especially in adolescent rats which showed preference at shorter puff delivery durations (lower nicotine doses) compared with adults. Together, these findings suggest that OV provides an affordable, open-source option for preclinical behavioral research into the effects of vaping.

Keywords: JUUL; adolescent; e-cigarette; nicotine; reward; vaping.

Graphical abstract

Figure 1.

Labeled schematic of the OV system.

Figure 2.

Wiring diagram for OV apparatus.

Figure 3.

Custom PCB design to facilitate building the OV apparatus.

Figure 4.

Visual schematic outlining the CPP paradigm. Figure made using BioRender.

Figure 5.

Plasma concentrations for nicotine (left) and cotinine (right) at 10 or 120 min after termination of a 10-min total exposure session during which vapor was delivered for one of 2, 4, or 8 min. Data represented as mean ± standard error of the mean (SEM); #p < 0.0001 120- versus 10-min time point; *p < 0.05 dose trend.

Figure 6.

Nicotine vapor CPP in adult and adolescent (PND30–PND39) rats; *p < 0.0125 postconditioned versus preconditioned (Bonferroni corrected). Data represented as mean ± SEM.