Depolarizing effect of various local anaesthetics on the Helix aspersa neurons: dose-response relationship.
The depolarizing effect of various local anaesthetics (LA) on the membrane potential of Helix central neurons has been examined. There is a relation between depolarizing effect and concentration of LA in the bath that is linear over a range of concentrations. The slope of the curve is significantly higher for amethocaine (tetracaine) than for procaine while for dibucaine the dose-response relation is not linear. The blockade of a response to acetylcholine (ACh) is about two fold higher for dibucaine and amethocaine than for procaine. These results suggest that both amethocaine and procaine act at the ACh-site in addition to their binding with specific sites located within the ionic channel lumen; dibucaine appears to act through another mechanism.
D000779:Anesthetics, Local / Q000494:pharmacology*; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D005724:Ganglia / Q000187:drug effects; D006372:Helix, Snails / Q000502:physiology*; D006584:Hexamethonium Compounds / Q000494:pharmacology; D066298:In Vitro Techniques; D007478:Iontophoresis; D008564:Membrane Potentials / Q000187:drug effects; D009467:Neuromuscular Depolarizing Agents; D009474:Neurons / Q000187:drug effects*
D000779:Anesthetics, Local; D006584:Hexamethonium Compounds; D009467:Neuromuscular Depolarizing Agents; D001285:Atropine