title: Quantal analysis indicates an alpha-toxin-like block by lophotoxin, a non-ionic marine natural product.
abstract: The effects of a structurally novel paralytic substance (lophotoxin) on quantal transmission parameters and the time course of synaptic potentials have been examined. This substance completely abolished potentials by reducing quantal size without affecting the release of quanta. Nerve conduction, membrane potential, and the passive electrical properties of the muscle end-plate remained unaffected. Lophotoxin appears to act directly on the acetylcholine receptor-channel complex, although perhaps not the cholinoreceptive site itself, as suggested by the unusual chemistry and onset kinetics of this toxin.
mesh_terms: D000818:Animals; D002038:Bungarotoxins / Q000494:pharmacology; D003064:Cnidarian Venoms / Q000494:pharmacology*; D004224:Diterpenes / Q000494:pharmacology*; D005071:Evoked Potentials / Q000187:drug effects; D009045:Motor Endplate / Q000187:drug effects* / Q000502:physiology; D009466:Neuromuscular Blocking Agents / Q000494:pharmacology*; D009469:Neuromuscular Junction / Q000187:drug effects*; D011894:Rana pipiens; D011950:Receptors, Cholinergic / Q000502:physiology; D013729:Terpenes
chemical_list: D002038:Bungarotoxins; D003064:Cnidarian Venoms; D004224:Diterpenes; D009466:Neuromuscular Blocking Agents; D011950:Receptors, Cholinergic; D013729:Terpenes; C030303:lophotoxin