title: The antagonism between botulinum toxin and calcium in motor nerve terminals.
abstract: The effects of tetraethylammonium and manganese, which modify calcium entry into motor nerve terminals, have been studied during advanced stages of botulinum paralysis. Evidence has been obtained that the voltage-activated calcium current in the nerve endings is not significantly reduced by botulinum toxin. The depression of transmitter release that the toxin produces must arise at a later stage, at an intracellular site of the release mechanism.
mesh_terms: D000109:Acetylcholine / Q000378:metabolism; D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001905:Botulinum Toxins / Q000494:pharmacology*; D002118:Calcium / Q000037:antagonists & inhibitors*; D008345:Manganese / Q000494:pharmacology; D009411:Nerve Endings / Q000187:drug effects; D009469:Neuromuscular Junction / Q000187:drug effects*; D011896:Rana temporaria; D012636:Secretory Rate / Q000187:drug effects; D013757:Tetraethylammonium Compounds / Q000494:pharmacology
chemical_list: D013757:Tetraethylammonium Compounds; D008345:Manganese; D001905:Botulinum Toxins; D000109:Acetylcholine; D002118:Calcium