(R)-(5-tert-butyl-2,3-dihydro-1H-inden-1-yl)-3-(1H-indazol-4-yl)-urea (ABT-102) blocks polymodal activation of transient receptor potential vanilloid 1 receptors in vitro and heat-evoked firing of spinal dorsal horn neurons in vivo

J Pharmacol Exp Ther. 2008 Sep;326(3):879-88. doi: 10.1124/jpet.108.138511. Epub 2008 May 30.

Abstract

The transient receptor potential vanilloid (TRPV) 1 receptor, a nonselective cation channel expressed on peripheral sensory neurons and in the central nervous system, plays a key role in pain. TRPV1 receptor antagonism is a promising approach for pain management. In this report, we describe the pharmacological and functional characteristics of a structurally novel TRPV1 antagonist, (R)-(5-tert-butyl-2,3-dihydro-1H-inden-1-yl)-3-(1H-indazol-4-yl)-urea (ABT-102), which has entered clinical trials. At the recombinant human TRPV1 receptor ABT-102 potently (IC(50) = 5-7 nM) inhibits agonist (capsaicin, N-arachidonyl dopamine, anandamide, and proton)-evoked increases in intracellular Ca(2+) levels. ABT-102 also potently (IC(50) = 1-16 nM) inhibits capsaicin-evoked currents in rat dorsal root ganglion (DRG) neurons and currents evoked through activation of recombinant rat TRPV1 currents by capsaicin, protons, or heat. ABT-102 is a competitive antagonist (pA(2) = 8.344) of capsaicin-evoked increased intracellular Ca(2+) and shows high selectivity for blocking TRPV1 receptors over other TRP receptors and a range of other receptors, ion channels, and transporters. In functional studies, ABT-102 blocks capsaicin-evoked calcitonin gene-related peptide release from rat DRG neurons. Intraplantar administration of ABT-102 blocks heat-evoked firing of wide dynamic range and nociceptive-specific neurons in the spinal cord dorsal horn of the rat. This effect is enhanced in a rat model of inflammatory pain induced by administration of complete Freund's adjuvant. Therefore, ABT-102 potently blocks multiple modes of TRPV1 receptor activation and effectively attenuates downstream consequences of receptor activity. ABT-102 is a novel and selective TRPV1 antagonist with pharmacological and functional properties that support its advancement into clinical studies.

Publication types

  • Comparative Study

MeSH terms

  • Action Potentials / drug effects
  • Action Potentials / physiology*
  • Animals
  • Cell Line
  • Cells, Cultured
  • Dose-Response Relationship, Drug
  • Hot Temperature*
  • Humans
  • Indazoles / chemistry
  • Indazoles / pharmacology*
  • Male
  • Posterior Horn Cells / drug effects
  • Posterior Horn Cells / metabolism*
  • Rats
  • Rats, Sprague-Dawley
  • TRPV Cation Channels / antagonists & inhibitors*
  • TRPV Cation Channels / metabolism*
  • Urea / analogs & derivatives*
  • Urea / chemistry
  • Urea / pharmacology

Substances

  • ABT 102
  • Indazoles
  • TRPV Cation Channels
  • TRPV1 receptor
  • Urea