title: Veratridine-stimulated release of amine conjugates from centrifugal fibers in the Limulus peripheral visual system.
abstract: Centrifugal fibers that originate in the brain and project to the Limulus peripheral visual system synthesize and store octopamine and conjugates of octopamine and tyramine. In a previous study we showed that depolarization, induced by elevating extracellular K+, stimulated a preferential release of octopamine from these fibers. Here we show that veratridine-induced depolarization stimulates a rapid, transient release of octopamine and a delayed, sustained release of amine conjugates. Veratridine-stimulated release of both octopamine and amine conjugates depends on the influx of extracellular Ca2+ and is blocked by tetrodotoxin or the absence of extracellular Na+. The depolarization-stimulated release of amine conjugates raises the possibility that these molecules serve as intercellular messengers in the Limulus peripheral visual system.
authors.forename: B A
authors.initials: BA
authors.lastname: Battelle
authors.forename: J A
authors.initials: JA
authors.lastname: Evans
mesh_terms: D000588:Amines / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000378:metabolism; D002118:Calcium / Q000494:pharmacology; D004525:Efferent Pathways / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D005123:Eye / Q000294:innervation / Q000378:metabolism; D006737:Horseshoe Crabs / Q000378:metabolism*; D008854:Microscopy, Electron; D009655:Octopamine / Q000378:metabolism; D011188:Potassium / Q000494:pharmacology; D012964:Sodium / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D014439:Tyramine / Q000378:metabolism; D014701:Veratridine / Q000494:pharmacology*; D014702:Veratrine / Q000031:analogs & derivatives*
chemical_list: D000588:Amines; D009655:Octopamine; D013779:Tetrodotoxin; D014701:Veratridine; D012964:Sodium; D014702:Veratrine; D011188:Potassium; D002118:Calcium; D014439:Tyramine