Bitter tastants and artificial sweeteners activate a subset of epithelial cells in acute tissue slices of the rat trachea

Sci Rep. 2019 Jun 20;9(1):8834. doi: 10.1038/s41598-019-45456-w.

Abstract

Bitter and sweet receptors (T2Rs and T1Rs) are expressed in many extra-oral tissues including upper and lower airways. To investigate if bitter tastants and artificial sweeteners could activate physiological responses in tracheal epithelial cells we performed confocal Ca2+ imaging recordings on acute tracheal slices. We stimulated the cells with denatonium benzoate, a T2R agonist, and with the artificial sweeteners sucralose, saccharin and acesulfame-K. To test cell viability we measured responses to ATP. We found that 39% of the epithelial cells responding to ATP also responded to bitter stimulation with denatonium benzoate. Moreover, artificial sweeteners activated different percentages of the cells, ranging from 5% for sucralose to 26% for saccharin, and 27% for acesulfame-K. By using carbenoxolone, a gap junction blocker, we excluded that responses were mainly mediated by Ca2+ waves through cell-to-cell junctions. Pharmacological experiments showed that both denatonium and artificial sweeteners induced a PLC-mediated release of Ca2+ from internal stores. In addition, bitter tastants and artificial sweeteners activated a partially overlapping subpopulation of tracheal epithelial cells. Our results provide new evidence that a subset of ATP-responsive tracheal epithelial cells from rat are activated by both bitter tastants and artificial sweeteners.

MeSH terms

  • Animals
  • Calcium / metabolism
  • Calcium Signaling
  • Epithelial Cells / drug effects
  • Epithelial Cells / metabolism*
  • Rats
  • Receptors, G-Protein-Coupled / agonists*
  • Receptors, G-Protein-Coupled / drug effects
  • Receptors, G-Protein-Coupled / metabolism
  • Saccharin / pharmacology
  • Sucrose / analogs & derivatives
  • Sucrose / pharmacology
  • Sweetening Agents / pharmacology*
  • Taste / physiology*
  • Thiazines / pharmacology
  • Trachea / cytology*
  • Trachea / diagnostic imaging

Substances

  • Receptors, G-Protein-Coupled
  • Sweetening Agents
  • Thiazines
  • taste receptors, type 1
  • taste receptors, type 2
  • Sucrose
  • trichlorosucrose
  • Saccharin
  • acetosulfame
  • Calcium