PLCbeta2-independent behavioral avoidance of prototypical bitter-tasting ligands

Chem Senses. 2005 Sep;30(7):593-600. doi: 10.1093/chemse/bji053. Epub 2005 Aug 31.


Using a brief-access taste assay, we show in the present report that although phospholipase C beta2 knockout (PLCbeta2 KO) mice are unresponsive to low- and midrange concentrations of quinine and denatonium, they do significantly avoid licking higher concentrations of these aversive compounds. PLCbeta2 KO mice displayed no concentration-dependent licking of the prototypical sweetener sucrose but were similar to wild-type mice in their responses to citric acid and NaCl, notwithstanding some interesting exceptions. Although these findings confirm an essential role for PLCbeta2 in taste responsiveness to sucrose and to low- to midrange concentrations of quinine and denatonium in mice as previously reported, they importantly suggest that higher concentrations of the latter two compounds, which are bitter to humans, can engage a PLCbeta2-independent taste transduction pathway.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Avoidance Learning / physiology*
  • Dose-Response Relationship, Drug
  • Ligands
  • Mice
  • Mice, Knockout
  • Nerve Tissue Proteins / deficiency
  • Nerve Tissue Proteins / physiology*
  • Phosphoinositide Phospholipase C
  • Quaternary Ammonium Compounds / administration & dosage
  • Quinine / administration & dosage
  • Sensory Thresholds
  • Signal Transduction
  • Stimulation, Chemical
  • Sucrose / administration & dosage
  • Taste*
  • Type C Phospholipases / deficiency
  • Type C Phospholipases / physiology*


  • Ligands
  • Nerve Tissue Proteins
  • Quaternary Ammonium Compounds
  • denatonium benzoate
  • Sucrose
  • Quinine
  • Type C Phospholipases
  • Phosphoinositide Phospholipase C
  • Plch2 protein, mouse