Differential effects of omega-conotoxin GVIA and MVIIC on nerve stimulation induced contractions of guinea-pig ileum and rat vas deferens

Eur J Pharmacol. 1994 Jun 2;258(1-2):155-8. doi: 10.1016/0014-2999(94)90069-8.


omega-Conotoxin GVIA and omega-conotoxin MVIIC caused similar concentration-dependent reductions of the electrically induced twitch responses of guinea-pig ileum. The inhibitory effects of omega-conotoxin GVIA were long-lasting whereas those to omega-conotoxin MVIIC were readily reversed. Preincubation with omega-conotoxin MVIIC prevented the irreversible inhibition of omega-conotoxin GVIA suggesting a common site of interaction. However, unlike omega-conotoxin GVIA which caused inhibition, omega-conotoxin MVIIC did not affect the electrically induced twitch responses of the rat vas deferens nor did it prevent the irreversible inhibition with omega-conotoxin GVIA. This study indicates the possible existence of different subtypes of the N-type voltage-dependent calcium channel.

MeSH terms

  • Animals
  • Dose-Response Relationship, Drug
  • Electric Stimulation
  • Guinea Pigs
  • Ileum / drug effects*
  • Ileum / innervation
  • In Vitro Techniques
  • Male
  • Muscle Contraction / drug effects
  • Muscle, Smooth / drug effects*
  • Neurons / drug effects
  • Neurons / physiology
  • Peptides / pharmacology*
  • Rats
  • Vas Deferens / drug effects*
  • Vas Deferens / innervation
  • omega-Conotoxin GVIA
  • omega-Conotoxins*


  • Peptides
  • omega-Conotoxins
  • omega-conotoxin-MVIIC
  • omega-Conotoxin GVIA