TRPV1 feed-forward sensitisation depends on COX2 upregulation in primary sensory neurons

Sci Rep. 2021 Feb 10;11(1):3514. doi: 10.1038/s41598-021-82829-6.

Abstract

Increased activity and excitability (sensitisation) of a series of molecules including the transient receptor potential ion channel, vanilloid subfamily, member 1 (TRPV1) in pain-sensing (nociceptive) primary sensory neurons are pivotal for developing pathological pain experiences in tissue injuries. TRPV1 sensitisation is induced and maintained by two major mechanisms; post-translational and transcriptional changes in TRPV1 induced by inflammatory mediators produced and accumulated in injured tissues, and TRPV1 activation-induced feed-forward signalling. The latter mechanism includes synthesis of TRPV1 agonists within minutes, and upregulation of various receptors functionally linked to TRPV1 within a few hours, in nociceptive primary sensory neurons. Here, we report that a novel mechanism, which contributes to TRPV1 activation-induced TRPV1-sensitisation within ~ 30 min in at least ~ 30% of TRPV1-expressing cultured murine primary sensory neurons, is mediated through upregulation in cyclooxygenase 2 (COX2) expression and increased synthesis of a series of COX2 products. These findings highlight the importance of feed-forward signalling in sensitisation, and the value of inhibiting COX2 activity to control pain, in nociceptive primary sensory neurons in tissue injuries.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Capsaicin / pharmacology
  • Cyclooxygenase 2 / metabolism*
  • Ganglia, Spinal / metabolism
  • Inflammation Mediators / metabolism
  • Mice
  • Neurons / metabolism*
  • Pain / metabolism
  • TRPV Cation Channels / genetics
  • TRPV Cation Channels / metabolism*
  • Transient Receptor Potential Channels / metabolism
  • Up-Regulation / drug effects

Substances

  • Inflammation Mediators
  • TRPV Cation Channels
  • TRPV1 protein, mouse
  • Transient Receptor Potential Channels
  • Cyclooxygenase 2
  • Capsaicin