A novel function of synapsin II in neurotransmitter release

Takashi Sugiyama, Toru Shinoe, Yoko Ito, Hidemi Misawa, Takuro Tojima, Etsuro Ito, Tohru Yoshioka

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


Although synapsin has been localized to presynaptic structures, its function remains poorly understood. In the present study, we investigated the presynaptic function of synapsin II using a synaptic vesicle recycling process using synapsin-II-overexpressing NG108-15 cells. Western blot analysis with antibodies for synaptic-vesicle-associated protein indicated that the number of synaptic vesicles was approximately doubled in synapsin II transfectants as reported previously. In differentiated synapsin-II-overexpressing and control cells, the application of high potassium induced strong intracellular calcium elevation along neurites and varicosities after differentiation and a weak calcium rise in the cell bodies. The uptake and release of the fluorescent dye FM1-43 revealed that synaptic vesicle recycling in synapsin-II-transfected cells occurred with the same kinetics in the cell body and neuritic varicosities. Furthermore, the area labeled with FM1-43 fluorescence in the synapsin-II-transfected cells was approximately twice as much as in control cells after stimulation, and ATP released after synaptic vesicle fusion with the plasma membrane in synapsin-II-expressing cells was significantly elevated relative to controls. The number of synaptic vesicles paralleled the amount of transmitter released from the cells leading to the conclusion that the number of releasable synaptic vesicles were increased by synapsin II transfection into NG108-15 cells, suggesting that synapsin II may have a role in the regulation of synaptic vesicle number in presynapse-like structures in NG108-15 cells.

Original languageEnglish
Pages (from-to)133-143
Number of pages11
JournalMolecular Brain Research
Issue number1-2
Publication statusPublished - 2000 Dec 28
Externally publishedYes


  • ATP release
  • Ca imaging
  • FM1-43
  • NG108-15
  • Synapsin
  • Synaptic vesicle recycling

ASJC Scopus subject areas

  • Molecular Biology
  • Cellular and Molecular Neuroscience


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