Polymorphisms in TRPV1 and TAS2Rs associate with sensations from sampled ethanol

Genetic variation in chemosensory genes can explain variability in individual's perception of and preference for many foods and beverages. To gain insight into variable preference and intake of alcoholic beverages, we explored individual variability in the responses to sampled ethanol (EtOH). In humans, EtOH elicits sweet, bitter, and burning sensations. Here, we explore the relationship between variation in EtOH sensations and polymorphisms in genes encoding bitter taste receptors (TAS2Rs) and a polymodal nociceptor (TRPV1).

Caucasian participants (n = 93) were genotyped for 16 single nucleotide polymorphisms (SNPs) in TRPV1, 3 SNPs in TAS2R38, and 1 SNP in TAS2R13. Participants rated sampled EtOH on a generalized Labeled Magnitude Scale. Two stimuli were presented: a 16% EtOH whole-mouth sip-and-spit solution with a single time-point rating of overall intensity and a cotton swab saturated with 50% EtOH on the circumvallate papillae (CV) with ratings of multiple qualities over 3 minutes. Area-under-the-curve (AUC) was calculated for the time-intensity data.

The EtOH whole-mouth solution had overall intensity ratings near "very strong." Burning/stinging had the highest mean AUC values, followed by bitterness and sweetness. Whole-mouth intensity ratings were significantly associated with burning/stinging and bitterness AUC values on the CV. Three TRPV1 SNPs (rs224547, rs4780521, rs161364) were associated with EtOH sensations on the CV, with 2 (rs224547 and rs4780521) exhibiting strong linkage disequilibrium. Additionally, the TAS2R38 SNPs rs713598, rs1726866, and rs10246939 formed a haplotype, and were associated with bitterness on the CV. Last, overall intensity for whole-mouth EtOH associated with the TAS2R13 SNP rs1015443.

These data suggest genetic variation in TRPV1 and TAS2Rs influence sensations from sampled EtOH and may potentially influence how individuals initially respond to alcoholic beverages.