Menthol and Addiction
Meet the Scientist
I’m Deniz Bagdas, Ph.D. (@science.notes on IG), a postdoctoral associate at VCU. My research focuses on the role of nicotinic acetylcholine receptors (nAChR) in nicotine addiction and pain, specifically impact of menthol on nicotine dependence.
Menthol, found naturally in mint and added to some cigarettes, is preferred by ~25% of US smokers. Mentholated cigarette smokers find it harder to quit. Demographically, they tend to be preferred by African-Americans, females, and young individuals initiating smoking.
Importantly, menthol additive may inhibit nicotine metabolism. Menthol is a ligand for transient receptor potential (TRP) cation channels, including TRPM8 (cold-sensitive channels). Menthol’s sensory effects may lead to an increase in nicotine intake through a “cooling” effect and/or masking of the nicotine’s bitter taste. Oral menthol can reduce the aversive effects of oral nicotine through TRPM8 receptor involvement. However, menthol is also a non-competitive antagonist for multiple nAChRs. Thus, menthol is a flavoring agent with pharmacological characteristics that can modulate the effects of nicotine on its receptors.
Menthol is reported to enhance the reinforcing actions of nicotine. My recent findings showed that menthol: 1) increases nicotine reward-like effects via central and sensory mechanisms, 2) alters nicotine-induced dopamine signaling in the nucleus accumbens, a brain region associated with nicotine reward. It has recently been reported that menthol enhances reward-like behavior of nicotine by potentiating nicotine-induced changes in nAChR function, nAChR upregulation, and dopamine neuron excitability. Further, mentholated cigarettes smoking, or oral mentholated nicotine products consumption, have increased in youth in the last two decades. Therefore, menthol may increase the risk ratio for nicotine addiction in youth. My latest data revealed that menthol increases nicotine consumption in a sex-, age- and concentration-dependent manner.
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