Lower expressions of the human bitter taste receptor TAS2R in smokers: reverse transcriptase-polymerase chain reaction analysis

Mieko Aoki; Tetsuya Takao; Kyoichi Takao; Fumihiko Koike; Narufumi Suganuma

doi:10.1186/1617-9625-12-12

Lower expressions of the human bitter taste receptor TAS2R in smokers: reverse transcriptase-polymerase chain reaction analysis

Tob Induc Dis. 2014 Aug 15;12(1):12. doi: 10.1186/1617-9625-12-12. eCollection 2014.

Authors

Mieko Aoki¹, Tetsuya Takao², Kyoichi Takao³, Fumihiko Koike⁴, Narufumi Suganuma⁵

Affiliations

¹ Department of food and nutrition, Sanyo Gakuen College, 1-14-1 Hirai, Naka-ward, Okayama 703-8501, Japan.
² Department of nutrition and health promotion, Showa Women's University, Tokyo, Japan.
³ School of Medicine, Nihon University, Tokyo, Japan.
⁴ Department of Dentistry and Oral Surgery, Nihon University, Tokyo, Japan.
⁵ Department of Medicine, Kochi University, Kochi, Japan.

Abstract

Background: Despite the fact that smokers have deficit in detecting taste, particularly bitter taste, no study has investigated its biological correlate.

Methods: In this context, we compared the expression of the bitter taste receptor gene, taste 2 receptor (TAS2R) in the tongues of smokers and non-smokers. Tissue samples were collected from the lateral portion of the tongues of 22 smokers and 22 age- and gender-matched healthy volunteers (19 males and three females) with no history of smoking. Reverse transcriptase-polymerase chain reaction was used to examine the expression of TAS2R in the two groups, and the effect of aging on TAS2R expression was also assessed.

Results: TAS2R expression was significantly lower among smokers than non-smokers (t = 6.525, P < .0001, 11.36 ± 6.0 vs. 2.09 ± 2.8, mean ± SD, non-smokers vs. smokers). Further, a positive correlation between age and expression of TAS2R was observed in non-smokers (r = .642, P = .001), but not smokers (r = .124, P = .584). This correlation difference was significant (Z = 1.96, P = .0496).

Conclusions: Smokers showed a significantly lower expression of the bitter taste receptor gene than non-smokers, which is potentially caused by their inability to acquire such receptors with age because of cigarette smoking, in contrast to non-smokers.

Keywords: Cigarette; Human; RT-PCR; TAS2R.