Light chain of botulinum neurotoxin is active in mammalian motor nerve terminals when delivered via liposomes

摘要: Liposomal encapsulation of the individual light and heavy chain botulinum neurotoxin A was used to investigate their intra-cellular effects on synaptic transmission at murine neuromuscular junction. Bath-application phrenic nerve-hemidiaphragms liposomes containing (up 75 nM) caused no alteration in neurally-evoked muscle tension. In contrast, with entrapped (9–20 nM final concentration) gave a pre-synaptic blockade that could be relieved temporarily by 4-aminopyridine, as for dichain toxin. Any contribution from contaminating intact toxin excluded both purity minimal toxicity mice preparations used, lack paralysis seen maximum amount native have been present liposomes. As bath-application high concentrations absence failed affect neurotransmiter release, it is concluded this alone can mimic action whole inside mammalian motor nerve endings, its predominant site action. Thus, provide more effective probe an component concerned Ca2+-dependent secretion.