Differential effects of omega-conotoxin GVIA and MVIIC on nerve stimulation induced contractions of guinea-pig ileum and rat vas deferens.
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.
Boot
J R
JR
Eli Lilly & Co., Lilly Research Centre Ltd., Windlesham, Surrey, UK.
D000818:Animals; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects* / Q000294:innervation; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D010455:Peptides / Q000494:pharmacology*; D051381:Rats; D014649:Vas Deferens / Q000187:drug effects* / Q000294:innervation; D020866:omega-Conotoxin GVIA; D020960:omega-Conotoxins
D010455:Peptides; D020960:omega-Conotoxins; C075851:omega-conotoxin-MVIIC; D020866:omega-Conotoxin GVIA