Direct evidence for a release of acetylcholine from the myenteric plexus of guinea pig small intestine by substance P.
Myenteric plexus-longitudinal muscle strips from guinea pig small intestine were labeled with [3H]choline while under continuous field stimulation. Release of newly synthesized [3H]acetylcholine was studied in the presence of substance P afterwards. Substance P evoked release of [3H]acetylcholine in a dose-related fashion. Both tetrodotoxin and [D-Pro2,D-Phe7,D-Trp9]substance P, a synthetic antagonist of substance P, completely blocked this release and provided evidence for a cholinergically mediated mechanism of substance P on enteric neurons.
D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007421:Intestine, Small / Q000378:metabolism*; D009197:Myenteric Plexus / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D013373:Substance P / Q000031:analogs & derivatives / Q000494:pharmacology*; D013779:Tetrodotoxin / Q000494:pharmacology
D013373:Substance P; D013779:Tetrodotoxin; D000109:Acetylcholine