Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Compound vesicle fusion increases quantal size and potentiates synaptic transmission

This article has been updated

Abstract

Exocytosis at synapses involves fusion between vesicles and the plasma membrane1. Although compound fusion between vesicles2,3 was proposed to occur at ribbon-type synapses4,5, whether it exists, how it is mediated, and what role it plays at conventional synapses remain unclear. Here we report the existence of compound fusion, its underlying mechanism, and its role at a nerve terminal containing conventional active zones in rats and mice. We found that high potassium application and high frequency firing induced giant capacitance up-steps, reflecting exocytosis of vesicles larger than regular ones, followed by giant down-steps, reflecting bulk endocytosis. These intense stimuli also induced giant vesicle-like structures, as observed with electron microscopy, and giant miniature excitatory postsynaptic currents (mEPSCs), reflecting more transmitter release. Calcium and its sensor for vesicle fusion, synaptotagmin, were required for these giant events. After high frequency firing, calcium/synaptotagmin-dependent mEPSC size increase was paralleled by calcium/synaptotagmin-dependent post-tetanic potentiation. These results suggest a new route of exocytosis and endocytosis composed of three steps. First, calcium/synaptotagmin mediates compound fusion between vesicles. Second, exocytosis of compound vesicles increases quantal size, which increases synaptic strength and contributes to the generation of post-tetanic potentiation. Third, exocytosed compound vesicles are retrieved via bulk endocytosis. We suggest that this vesicle cycling route be included in models of synapses in which only vesicle fusion with the plasma membrane is considered1.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Giant capacitance up- and down-steps.
Figure 2: Calcium/Syt2 mediates compound fusion.
Figure 3: KCl induces calcium/Syt2-dependent increase of the mEPSC size.
Figure 4: Calcium/Syt2-dependent PTP and quantal size increase.

Similar content being viewed by others

Change history

  • 07 May 2009

    Error bars were added to the third panel of Fig. 4a on 7 May 2009.

References

  1. Sudhof, T. C. The synaptic vesicle cycle. Annu. Rev. Neurosci. 27, 509–547 (2004)

    Article  Google Scholar 

  2. Alvarez, d. T. & Fernandez, J. M. Compound versus multigranular exocytosis in peritoneal mast cells. J. Gen. Physiol. 95, 397–409 (1990)

    Article  Google Scholar 

  3. Scepek, S. & Lindau, M. Focal exocytosis by eosinophils—compound exocytosis and cumulative fusion. EMBO J. 12, 1811–1817 (1993)

    Article  CAS  Google Scholar 

  4. Heidelberger, R., Heinemann, C., Neher, E. & Matthews, G. Calcium dependence of the rate of exocytosis in a synaptic terminal. Nature 371, 513–515 (1994)

    Article  ADS  CAS  Google Scholar 

  5. Matthews, G. & Sterling, P. Evidence that vesicles undergo compound fusion on the synaptic ribbon. J. Neurosci. 28, 5403–5411 (2008)

    Article  CAS  Google Scholar 

  6. He, L., Wu, X. S., Mohan, R. & Wu, L. G. Two modes of fusion pore opening revealed by cell-attached recordings at a synapse. Nature 444, 102–105 (2006)

    Article  ADS  CAS  Google Scholar 

  7. Sätzler, K. et al. Three-dimensional reconstruction of a calyx of Held and its postsynaptic principal neuron in the medial nucleus of the trapezoid body. J. Neurosci. 22, 10567–10579 (2002)

    Article  Google Scholar 

  8. Gentet, L. J., Stuart, G. J. & Clements, J. D. Direct measurement of specific membrane capacitance in neurons. Biophys. J. 79, 314–320 (2000)

    Article  CAS  Google Scholar 

  9. Heuser, J. E. & Reese, T. S. Evidence for recycling of synaptic vesicle membrane during transmitter release at the frog neuromuscular junction. J. Cell Biol. 57, 315–344 (1973)

    Article  CAS  Google Scholar 

  10. de Lange, R. P., de Roos, A. D. & Borst, J. G. Two modes of vesicle recycling in the rat calyx of Held. J. Neurosci. 23, 10164–10173 (2003)

    Article  CAS  Google Scholar 

  11. Richards, D. A., Guatimosim, C. & Betz, W. J. Two endocytic recycling routes selectively fill two vesicle pools in frog motor nerve terminals. Neuron 27, 551–559 (2000)

    Article  CAS  Google Scholar 

  12. Coggins, M. R., Grabner, C. P., Almers, W. & Zenisek, D. Stimulated exocytosis of endosomes in goldfish retinal bipolar neurons. J. Physiol. (Lond.) 584, 853–865 (2007)

    Article  CAS  Google Scholar 

  13. Xu, J. et al. GTP-independent rapid and slow endocytosis at a central synapse. Nature Neurosci. 11, 45–53 (2008)

    Article  CAS  Google Scholar 

  14. Sun, J. et al. A dual-Ca2+-sensor model for neurotransmitter release in a central synapse. Nature 450, 676–682 (2007)

    Article  ADS  CAS  Google Scholar 

  15. Korogod, N., Lou, X. & Schneggenburger, R. Presynaptic Ca2+ requirements and developmental regulation of posttetanic potentiation at the calyx of Held. J. Neurosci. 25, 5127–5137 (2005)

    Article  CAS  Google Scholar 

  16. Habets, R. L. & Borst, J. G. Post-tetanic potentiation in the rat calyx of Held synapse. J. Physiol. (Lond.) 564, 173–187 (2005)

    Article  CAS  Google Scholar 

  17. Zucker, R. S. & Regehr, W. G. Short-term synaptic plasticity. Annu. Rev. Physiol. 64, 355–405 (2002)

    Article  CAS  Google Scholar 

  18. Heuser, J. E. A possible origin of the 'giant' spontaneous potentials that occur after prolonged transmitter release at frog neuromuscular junctions. J. Physiol. (Lond.) 239, 106P–108P (1974)

    CAS  Google Scholar 

  19. Henze, D. A., McMahon, D. B., Harris, K. M. & Barrionuevo, G. Giant miniature EPSCs at the hippocampal mossy fiber to CA3 pyramidal cell synapse are monoquantal. J. Neurophysiol. 87, 15–29 (2002)

    Article  Google Scholar 

  20. Llano, I. et al. Presynaptic calcium stores underlie large-amplitude miniature IPSCs and spontaneous calcium transients. Nature Neurosci. 3, 1256–1265 (2000)

    Article  CAS  Google Scholar 

  21. Wall, M. J. & Usowicz, M. M. Development of the quantal properties of evoked and spontaneous synaptic currents at a brain synapse. Nature Neurosci. 1, 675–682 (1998)

    Article  CAS  Google Scholar 

  22. Del Castillo, J. & Katz, B. Quantal components of the end-plate potential. J. Physiol. (Lond.) 124, 560–573 (1954)

    Article  CAS  Google Scholar 

  23. Tong, G. & Jahr, C. E. Multivesicular release from excitatory synapses of cultured hippocampal neurons. Neuron 12, 51–59 (1994)

    Article  CAS  Google Scholar 

  24. Wadiche, J. I. & Jahr, C. E. Multivesicular release at climbing fiber-Purkinje cell synapses. Neuron 32, 301–313 (2001)

    Article  CAS  Google Scholar 

  25. Sun, J. Y. & Wu, L. G. Fast kinetics of exocytosis revealed by simultaneous measurements of presynaptic capacitance and postsynaptic currents at a central synapse. Neuron 30, 171–182 (2001)

    Article  CAS  Google Scholar 

  26. Singer, J. H., Lassova, L., Vardi, N. & Diamond, J. S. Coordinated multivesicular release at a mammalian ribbon synapse. Nature Neurosci. 7, 826–833 (2004)

    Article  CAS  Google Scholar 

  27. Paillart, C., Li, J., Matthews, G. & Sterling, P. Endocytosis and vesicle recycling at a ribbon synapse. J. Neurosci. 23, 4092–4099 (2003)

    Article  CAS  Google Scholar 

  28. Oertel, D. The role of timing in the brain stem auditory nuclei of vertebrates. Annu. Rev. Physiol. 61, 497–519 (1999)

    Article  CAS  Google Scholar 

  29. Boraud, T., Bezard, E., Bioulac, B. & Gross, C. E. From single extracellular unit recording in experimental and human Parkinsonism to the development of a functional concept of the role played by the basal ganglia in motor control. Prog. Neurobiol. 66, 265–283 (2002)

    Article  Google Scholar 

  30. Takamori, S. et al. Molecular anatomy of a trafficking organelle. Cell 127, 831–846 (2006)

    Article  CAS  Google Scholar 

  31. Lindau, M. & Alvarez de Toledo, G. The fusion pore. Biochim. Biophys. Acta 164, 167–173 (2003)

    Article  Google Scholar 

  32. Spruce, A. E., Breckenridge, L. J., Lee, A. K. & Almers, W. Properties of the fusion pore that forms during exocytosis of a mast cell secretory vesicle. Neuron 4, 643–654 (1990)

    Article  CAS  Google Scholar 

  33. Xu, J. & Wu, L. G. The decrease in the presynaptic calcium current is a major cause of short-term depression at a calyx-type synapse. Neuron 46, 633–645 (2005)

    Article  CAS  Google Scholar 

Download references

Acknowledgements

We thank J. Diamond and K. Paradiso for comments on the manuscript, and S. Cheng, R. Azzam and V. Crocker for help in EM. This work was supported by the National Institute of Neurological Disorders and Stroke Intramural Research Program (L.-G.W.) and the American Heart Association (R.A.).

Author Contributions L.H. performed cell-attached recordings; L.X. performed EM work, and the mEPSC and EPSC recordings; J.X. and B.D.M. helped with some experiments; L.B. helped with EM work and maintained Syt2-/- mice; E.M. and R.A. generated the Syt2-/- mouse line; and L.-G.W. supervised the project and wrote the paper.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Ling-Gang Wu.

Supplementary information

Supplementary Information

This file contains Supplementary Notes, Supplementary Results, Supplementary Methods, Supplementary Figures S1-S8 with Legends and Supplementary References (PDF 670 kb)

PowerPoint slides

Rights and permissions

Reprints and permissions

About this article

Cite this article

He, L., Xue, L., Xu, J. et al. Compound vesicle fusion increases quantal size and potentiates synaptic transmission. Nature 459, 93–97 (2009). https://doi.org/10.1038/nature07860

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature07860

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing