title: Patients with phantogeusia show increased expression of T2R taste receptor genes in their tongues.
abstract: OBJECTIVE
  The taste receptor gene family T2R has been implicated in the sensation of bitter taste. Phantogeusia is a spontaneous abnormal taste with no external stimulus. We analyzed the expression of T2R taste receptor genes in the tongues of patients with phantogeusia to assess their role in the pathogenesis of phantogeusia.
  
  
  METHODS
  We obtained specimens from 43 patients with phantogeusia and 24 normal volunteers by scraping the foliate papillae and examined these specimens for the expression of 10 T2R taste receptor genes using reverse transcription-polymerase chain reaction and electrophoresis.
  
  
  RESULTS
  The expression rate (subjects with detectable expression) of the 10 taste receptor genes in the healthy subjects ranged from 16.7% to 100%; 3 receptor genes were found in 50% or fewer of these subjects. In the patients with phantogeusia, the expression rate was increased significantly compared to that in the healthy control subjects for 3 of the 10 receptor genes examined.
  
  
  CONCLUSIONS
  Our results show that the expression rate of some of the T2R taste receptor genes was increased significantly in patients with phantogeusia. These results suggest that increased expression of taste receptor genes is involved in the pathogenesis of phantogeusia; this finding may contribute to elucidation of the mechanism of this disorder.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Ryoji
authors.initials: R
authors.lastname: Hirai
authors.forename: Kyoichi
authors.initials: K
authors.lastname: Takao
authors.forename: Keiko
authors.initials: K
authors.lastname: Onoda
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Kokubun
authors.forename: Minoru
authors.initials: M
authors.lastname: Ikeda
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D004586:Electrophoresis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012313:RNA / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013651:Taste Disorders / Q000235:genetics*; D014059:Tongue / Q000378:metabolism*; D000098706:Taste Receptors, Type 2
chemical_list: D043562:Receptors, G-Protein-Coupled; D000098706:Taste Receptors, Type 2; D012313:RNA