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Updated: Oct 18, 2026

Physiological Recordings of High and Low Output NMJs on the Crayfish Leg Extensor Muscle
Published on: November 17, 2010
Role of alpha-SNAP in promoting efficient neurotransmission at the crayfish neuromuscular junction
1T. H. Morgan School of Biological Science, University of Kentucky, Lexington 40506-0225, USA.
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.
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