Capsazepine block of voltage-activated calcium channels in adult rat dorsal root ganglion neurones in culture

Br J Pharmacol. 1997 Aug;121(7):1461-7. doi: 10.1038/sj.bjp.0701272.


1. We have found that capsazepine, a competitive antagonist at the vanilloid (capsaicin) receptor, blocks voltage-activated calcium currents in sensory neurones. 2. The block of calcium current was slow to develop with a half time of about one minute at 100 microM and lasted for the duration of the experiment. The rate of block of calcium current was strongly concentration-dependent. 3. The EC50 for the blocking effect at 0 mV was 7.7 +/- 1.4 microM after 6 min exposure to capsazepine. The EC50 at equilibrium was estimated to be 1.4 +/- 0.2 microM. 4. The block of calcium current showed some voltage-dependence but there was no indication of any selectivity of action for a calcium channel subtype. The characteristics of the blocking action of capsazepine on the residual current of cells which were pretreated with either omega-conotoxin or nimodipine were similar to control. 5. The data suggest that capsazepine, in addition to its competitive antagonism of vanilloid receptors, has a non-specific blocking action on voltage-activated calcium channels which should be taken into account when interpreting the effects of this substance on intact preparations in vitro or in vivo.

MeSH terms

  • Animals
  • Calcium Channel Blockers / pharmacology*
  • Calcium Channels / drug effects*
  • Capsaicin / analogs & derivatives*
  • Capsaicin / pharmacology
  • Cells, Cultured
  • Dose-Response Relationship, Drug
  • Female
  • Ganglia, Spinal / drug effects
  • Male
  • Peptides / pharmacology
  • Rats
  • Rats, Sprague-Dawley
  • Rats, Wistar
  • omega-Conotoxin GVIA


  • Calcium Channel Blockers
  • Calcium Channels
  • Peptides
  • omega-Conotoxin GVIA
  • capsazepine
  • Capsaicin