Presynaptic injection of syntaxin-specific antibodies blocks transmission in the squid giant synapse

M. Sugimori, C. K. Tong, M. Fukuda, J. E. Moreira, T. Kojima, K. Mikoshiba, R. Llinás

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)


A polyclonal antibody, raised against the squid (Loligo pealei) syntaxin I, inhibited Ca2+-dependent interaction of syntaxin with synaptotagmin C2A domain in vitro. Presynaptic injection of the anti-Loligo syntaxin IgG into the squid giant synapse blocked synaptic transmission without affecting the presynaptic action potential or the voltage-gated calcium current responsible for transmitter release. Repetitive presynaptic stimulation produced a gradual decrease in the amplitude of the postsynaptic potential as the synaptic block progressed, indicating that the antibody interferes with vesicular fusion. Confocal microscopy of the fluorescein-labelled anti- Loligo syntaxin IgG showed binding at the synaptic active zone, while ultrastructurally, an increase in synaptic vesicular numbers in synapses blocked when this antibody was observed. These results implicate syntaxin in the vesicular fusion step of transmitter release in concert with synaptotagmin.

Original languageEnglish
Pages (from-to)39-51
Number of pages13
Issue number1
Publication statusPublished - 1998 May 21
Externally publishedYes


  • Confocal microscopy
  • Synaptic transmission
  • Syntaxin I sequence
  • Vesicular fusion

ASJC Scopus subject areas

  • Neuroscience(all)


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