title: Role of alpha-SNAP in promoting efficient neurotransmission at the crayfish neuromuscular junction.
abstract: In this manuscript, we address the role of the soluble N-ethylmaleimide sensitive factor attachment protein (alpha-SNAP) in synaptic transmission at the neuromuscular junction of the crayfish opener muscle. Immunochemical methods confirm the presence of alpha-SNAP in these preparations and show that it is concentrated in the synaptic areas. Microinjection and electrophysiological studies show that alpha-SNAP causes an increase in neurotransmitter release yet does not significantly affect the kinetics. More specific quantal analysis, using focal, macropatch, synaptic current recordings, shows that alpha-SNAP increases transmitter release by increasing the probability of exocytosis but not the number of potential release sites. These data demonstrate that the role of alpha-SNAP is to increase the efficiency of neurotransmission by increasing the probability that a stimulus will result in neurotransmitter release. What this suggests is that alpha-SNAP is critical for the formation and maintenance of a "ready release" pool of synaptic vesicles.
authors.affiliation: T. H. Morgan School of Biological Science, University of Kentucky, Lexington 40506-0225, USA.
authors.forename: P
authors.initials: P
authors.lastname: He
authors.forename: R C
authors.initials: RC
authors.lastname: Southard
authors.forename: D
authors.initials: D
authors.lastname: Chen
authors.forename: S W
authors.initials: SW
authors.lastname: Whiteheart
authors.forename: R L
authors.initials: RL
authors.lastname: Cooper
mesh_terms: D000818:Animals; D003400:Astacoidea / Q000502:physiology*; D015153:Blotting, Western; D002352:Carrier Proteins / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D005455:Fluorescent Antibody Technique; D066298:In Vitro Techniques; D008565:Membrane Proteins / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D008845:Microinjections; D009132:Muscles / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D009154:Mutation / Q000502:physiology; D009469:Neuromuscular Junction / Q000187:drug effects / Q000502:physiology*; D052067:Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D033921:Vesicular Transport Proteins
chemical_list: D002352:Carrier Proteins; D008565:Membrane Proteins; D052067:Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins; D033921:Vesicular Transport Proteins