title: Effect of lignocaine on the responses produced by depolarizing agents at the chick neuromuscular junction.
abstract: The effect of lignocaine on the depolarization and contracture responses produced by acetylcholine (ACh) or tetraethylammonium (TEA) was studied in the isolated chick biventer cervicis (BVC) nerve-muscle preparation using the moving fluid electrode technique. Lignocaine (37 mumol X 1-1-1.8 mmol X 1-1) produced concentration-dependent contractures in the chick BVC muscle. The contractures produced by lignocaine were not accompanied by membrane depolarizations. ACh (5.5 mumol X 1-1-11.0 mmol X 1-1) and TEA (0.48-24.0 mmol X 1-1) produced concentration-dependent depolarizations and contractures in the chick BVC muscle. Lignocaine (0.93 mmol X 1-1) greatly reduced the responses produced by ACh, while it markedly increased the contracture responses produced by TEA. The depolarizations produced by TEA were reduced in lignocaine (0.93 mmol X 1-1). It was concluded that the local anaesthetic lignocaine produces contractures in the chick BVC muscle. Lignocaine potentiates the contractures produced by TEA, while it greatly reduces those produced by ACh.
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D002642:Chick Embryo; D004347:Drug Interactions; D066298:In Vitro Techniques; D008012:Lidocaine / Q000494:pharmacology*; D008723:Methohexital / Q000494:pharmacology; D009467:Neuromuscular Depolarizing Agents / Q000494:pharmacology*; D009469:Neuromuscular Junction / Q000187:drug effects*; D013757:Tetraethylammonium Compounds / Q000494:pharmacology
chemical_list: D009467:Neuromuscular Depolarizing Agents; D013757:Tetraethylammonium Compounds; D008012:Lidocaine; D008723:Methohexital; D000109:Acetylcholine