Inhibition of acid sensing ion channels by eugenol in rat trigeminal ganglion neurons

Neurosci Lett. 2023 Apr 23:803:137192. doi: 10.1016/j.neulet.2023.137192. Epub 2023 Mar 15.

Abstract

Eugenol is widely used as an analgesic in the dental treatment. The underlying mechanisms may involve its modulation of various ion channels. Acid-sensing ion channels (ASICs) are pH sensors and expressed in trigeminal ganglion (TG) neurons. In the present study, we found that eugenol concentration-dependently inhibited ASIC currents in TG neurons with an IC50 of 98.8 ± 7.4 μM. Eugenol decreased the maximum response to acidic pH and did not alter pH0.5 in the concentration-response curve of acidic pH, suggesting a noncompetitive inhibition of ASICs by eugenol. G-proteins were not involved in eugenol-induced inhibition, since pre-application of eugenol also decreased ASIC currents in the presence of the G-protein blocker GDP-β-S. In addition, eugenol also partly inhibited ASIC3 currents in Chinese hamster ovary cells transfected with ASIC3. In conclusion, eugenol partly inhibited ASIC currents in TG neurons in a concentration-dependent, non-competitive and G-protein independent manner. These results suggested that the ASICs could be a molecular target for eugenol in TG neurons, which contributed to its analgesic effect.

Keywords: Acid sensing ion channel; Electrophysiology; Eugenol; Rat; Trigeminal ganglion neurons.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acid Sensing Ion Channels*
  • Analgesics / pharmacology
  • Animals
  • CHO Cells
  • Cricetinae
  • Cricetulus
  • Eugenol* / pharmacology
  • Hydrogen-Ion Concentration
  • Neurons
  • Rats
  • Trigeminal Ganglion

Substances

  • Acid Sensing Ion Channels
  • Eugenol
  • Analgesics