Impact of vanilla flavor on nicotine taste, choice, intake, and seeking behaviors.

RATIONALE

Flavors can alter the orosensory properties of tobacco products. Specifically, flavors can serve as an oral cue for smokeless tobacco products.

OBJECTIVES

We aimed to investigate the impact of oral vanillin, the principal chemical of vanilla flavor in tobacco products, on nicotine's taste, and nicotine choice, intake, and seeking behaviors.

METHODS

Experiments were performed in young adult Sprague Dawley rats. We employed a two-bottle free-choice test (2BC) to measure the preference for different concentrations of vanillin and its effect on nicotine preference. To explore the long-term effects of early exposure to sweetened vanillin, we utilized a combined 2BC and intraoral self-administration (IOSA) model. We assessed the nicotine taking and seeking behaviors in the presence or absence of vanillin. We performed a taste reactivity test (TRT) to quantify liking (ingestive) and disliking (aversive) taste responses to oral nicotine with or without vanillin.

RESULTS

In 2BC, female rats preferred vanillin containing solutions more than their male counterparts. In IOSA, vanillin alone and in combination with nicotine led to greater IOSA compared to water. Female rats self-administered vanillin plus nicotine more than male rats. Vanillin increased motivation to nicotine taking, but only in females. In TRT, vanillin increased nicotine's ingestive responses but blocked aversive responses in both sexes.

CONCLUSIONS

These results indicate that vanilla flavor can increase oral nicotine intake. It can also increase liking and decrease disliking of nicotine's taste. Furthermore, the impact of vanilla flavor on nicotine taste and nicotine choice, intake, and seeking behaviors is concentration and sex dependent.