Sweet taste potentiates the reinforcing effects of e-cigarettes

Introduction:
This text presents the results of a study examining the impact of sweet taste on the reinforcing effects of e-cigarettes. The study adapted a flavor-nutrient conditioning paradigm to e-cigarettes and measured changes in wanting and liking ratings, as well as brain responses in the nucleus accumbens (NAcc) to conditioned cues.

Key Points:

* The study found that added sweetener can increase the reinforcing potential of an e-cigarette with and without nicotine via conditioning.
* Effective conditioning was reflected in moderate, but non-significant, increases of wanting and liking compared to the flavor only control.
* Large effects on increased NAcc response to the sight of e-cigarettes paired with sweet taste, relative to the control e-cigarettes, were observed.
* The magnitude of BOLD responses in the NAcc to the sight and the smell of the sweet-paired e-cigarettes correlated with changes in liking.
* Supra-additive effects of sweet+nicotine were observed in the NAcc as predicted.
* Nicotine was reinforcing after repeated use of the e-cigarette but failed in generalizing to liking and wanting for the nicotine-predictive e-cigarette flavors.
* Participants who disliked nicotine alone showed the strongest increase in liking for the e-cigarettes paired with sweet+nicotine.

Main Message:
The study suggests that sweet taste potentiates the reinforcing value of nicotine-containing e-cigarettes and that a mesocorticolimbic mechanism subserves this effect. The correspondence between liking and NAcc response supports this hypothesis, indicating that the activation is indicative of changes in reinforcement value and increased addictive potential. The findings suggest that sweeteners may increase the liability for abuse of alternative tobacco products, and that it could be beneficial to regulate the addition of sweeteners to e-cigarettes to reduce their overall appeal and reinforcing value. Such regulation may help to reduce continued use of alternative tobacco products following experimentation, which may ultimately reduce the incidence rates of nicotine dependence.

Kroemer, Nils B., Maria G. Veldhuizen, Roberta Delvy, Barkha P. Patel, Stephanie S. O’Malley, and Dana M. Small. “Sweet Taste Potentiates the Reinforcing Effects of E-Cigarettes.” European Neuropsychopharmacology 28, no. 10 (October 2018): 1089–1102. https://doi.org/10.1016/j.euroneuro.2018.07.102.