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:

Fast vesicle replenishment allows indefatigable signalling at the first auditory synapse

Abstract

Ribbon-type synapses in inner hair cells of the mammalian cochlea encode the complexity of auditory signals by fast and tonic release through fusion of neurotransmitter-containing vesicles. At any instant, only about 100 vesicles are tethered to the synaptic ribbon, and about 14 of these are docked to the plasma membrane1,2, constituting the readily releasable pool3. Although this pool contains about the same number of vesicles as that of conventional synapses4,5, ribbon release sites operate at rates of about two orders of magnitude higher3,6,7 and with submillisecond precision8,9,10,11. How these sites replenish their vesicles so efficiently remains unclear3,12,13. We show here, using two-photon imaging of single release sites in the intact cochlea, that preformed vesicles derived from cytoplasmic vesicle-generating compartments14 participate in fast release and replenishment. Vesicles were released at a maximal initial rate of 3 per millisecond during a depolarizing pulse, and were replenished at a rate of 1.9 per millisecond. We propose that such rapid resupply of vesicles enables temporally precise and sustained release rates. This may explain how the first auditory synapse can encode with indefatigable precision without having to rely on the slow, local endocytic vesicle cycle7.

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

Access options

Buy this article

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

Figure 1: Experimental design.
Figure 2: Imaging individual ribbon release sites.
Figure 3: Kinetics of release and recovery at individual release sites.
Figure 4: Quantification of vesicular release and recovery.

Similar content being viewed by others

References

  1. Liberman, M. C. Efferent synapses in the inner hair cell area of the cat cochlea: an electron microscopic study of serial sections. Hear. Res. 3, 189–204 (1980)

    Article  CAS  PubMed  Google Scholar 

  2. Saito, K. Fine structure of the sensory epithelium of the guinea pig organ of Corti: afferent and efferent synapses of hair cells. J. Ultrastruct. Res. 71, 222–232 (1980)

    Article  CAS  PubMed  Google Scholar 

  3. Moser, T. & Beutner, D. Kinetics of exocytosis and endocytosis at the cochlear inner hair cell afferent synapse of the mouse. Proc. Natl Acad. Sci. USA 97, 883–888 (2000)

    Article  CAS  ADS  PubMed  PubMed Central  Google Scholar 

  4. Schikorski, T. & Stevens, C. F. Quantitative ultrastructural analysis of hippocampal excitatory synapses. J. Neurosci. 17, 5858–5867 (1997)

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  5. Stevens, C. F. & Wang, Y. Facilitation and depression at single central synapses. Neuron 14, 795–802 (1995)

    Article  CAS  PubMed  Google Scholar 

  6. Rosenmund, C. & Stevens, C. F. Definition of the readily releasable pool of vesicles at hippocampal synapses. Neuron 16, 1197–1207 (1996)

    Article  CAS  PubMed  Google Scholar 

  7. Fernandez-Alfonso, T. & Ryan, T. A. The kinetics of synaptic vesicle pool depletion at CNS synaptic terminals. Neuron 41, 943–953 (2004)

    Article  CAS  PubMed  Google Scholar 

  8. Kiang, Y. Stimulus coding in the auditory nerve and cochlear nucleus. Acta Otolaryngol. (Stockh.) 59, 186–200 (1965)

    Article  Google Scholar 

  9. Johnson, D. H. The relationship between spike rate and synchrony in responses of auditory-nerve fibers to single tones. J. Acoust. Soc. Am. 68, 1115–1122 (1980)

    Article  CAS  ADS  PubMed  Google Scholar 

  10. Palmer, A. R. & Russell, I. J. Phase-locking in the cochlear nerve of the guinea-pig and its relation to the receptor potential of inner hair-cells. Hear. Res. 24, 1–15 (1986)

    Article  CAS  PubMed  Google Scholar 

  11. Sewell, W. F. in The Cochlea, Springer Handbook of Auditory Research Vol. 8 (eds Dallos, P., Popper, A. N. & Fay, R. R.) Ch. 9, 503–534 (Springer, New York, 1996)

    Google Scholar 

  12. Eisen, M. D., Spassova, M. & Parsons, T. D. Large releasable pool of synaptic vesicles in chick cochlear hair cells. J. Neurophysiol. 91, 2422–2428 (2004)

    Article  PubMed  Google Scholar 

  13. Edmonds, B. W., Gregory, F. D. & Schweizer, F. E. Evidence that fast exocytosis can be predominantly mediated by vesicles not docked at active zones in frog saccular hair cells. J. Physiol. (Lond.) 560, 439–450 (2004)

    Article  CAS  Google Scholar 

  14. Griesinger, C. B., Richards, C. D. & Ashmore, J. F. FM1-43 reveals membrane recycling in adult inner hair cells of the mammalian cochlea. J. Neurosci. 22, 3939–3952 (2002)

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  15. Mammano, F. & Ashmore, J. F. Reverse transduction measured in the isolated cochlea by laser Michelson interferometry. Nature 365, 838–841 (1993)

    Article  CAS  ADS  PubMed  Google Scholar 

  16. von Gersdorff, H., Vardi, E., Matthews, G. & Sterling, P. Evidence that vesicles on the synaptic ribbon of bipolar neurons can be rapidly released. Neuron 16, 1221–1227 (1996)

    Article  CAS  PubMed  Google Scholar 

  17. Spicer, S. S., Thomopoulos, G. N. & Schulte, B. A. Novel membranous structures in apical and basal compartments of inner hair cells. J. Comp. Neurol. 409, 424–437 (1999)

    Article  CAS  PubMed  Google Scholar 

  18. Beutner, D., Voets, T., Neher, E. & Moser, T. Calcium dependence of exocytosis and endocytosis at the cochlear inner hair cell afferent synapse. Neuron 29, 681–690 (2001)

    Article  CAS  PubMed  Google Scholar 

  19. Siegel, J. H. & Brownell, W. E. Presynaptic bodies in outer hair cells of the chinchilla organ of Corti. Brain Res. 220, 188–193 (1981)

    Article  CAS  PubMed  Google Scholar 

  20. Slepecky, N. B., Galsky, M. D., Swartzentruber-Martin, H. & Savage, J. Study of afferent nerve terminals and fibers in the gerbil cochlea: distribution by size. Hear. Res. 144, 124–134 (2000)

    Article  CAS  PubMed  Google Scholar 

  21. Smith, C. B. & Betz, W. J. Simultaneous independent measurement of endocytosis and exocytosis. Nature 380, 531–534 (1996)

    Article  CAS  ADS  PubMed  Google Scholar 

  22. Neves, G. & Lagnado, L. The kinetics of exocytosis and endocytosis in the synaptic terminal of goldfish retinal bipolar cells. J. Physiol. (Lond.) 515, 181–202 (1999)

    Article  CAS  Google Scholar 

  23. von Gersdorff, H. & Matthews, G. Depletion and replenishment of vesicle pools at a ribbon-type synaptic terminal. J. Neurosci. 17, 1919–1927 (1997)

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  24. Heidelberger, R., Sterling, P. & Matthews, G. Roles of ATP in depletion and replenishment of the releasable pool of synaptic vesicles. J. Neurophysiol. 88, 98–106 (2002)

    Article  CAS  PubMed  Google Scholar 

  25. Glowatzki, E. & Fuchs, P. A. Transmitter release at the hair cell ribbon synapse. Nature Neurosci. 5, 147–154 (2002)

    Article  CAS  PubMed  Google Scholar 

  26. Lenzi, D., Crum, J., Ellisman, M. H. & Roberts, W. M. Depolarization redistributes synaptic membrane and creates a gradient of vesicles on the synaptic body at a ribbon synapse. Neuron 36, 649–659 (2002)

    Article  CAS  PubMed  Google Scholar 

  27. Parsons, T. D. & Sterling, P. Synaptic ribbon. Conveyor belt or safety belt? Neuron 37, 379–382 (2003)

    Article  CAS  PubMed  Google Scholar 

  28. Zenisek, D., Steyer, J. A. & Almers, W. Transport, capture and exocytosis of single synaptic vesicles at active zones. Nature 406, 849–854 (2000)

    Article  CAS  ADS  PubMed  Google Scholar 

  29. Holt, M., Cooke, A., Neef, A. & Lagnado, L. High mobility of vesicles supports continuous exocytosis at a ribbon synapse. Curr. Biol. 14, 173–183 (2004)

    Article  CAS  PubMed  Google Scholar 

  30. Stevens, C. F. & Tsujimoto, T. Estimates for the pool size of releasable quanta at a single central synapse and for the time required to refill the pool. Proc. Natl Acad. Sci. USA 92, 846–849 (1995)

    Article  CAS  ADS  PubMed  PubMed Central  Google Scholar 

Download references

Acknowledgements

This work was supported by the MRC, the Wellcome Trust and a BBSRC Imaging grant to C.D.R. We thank U. Egert for his help with part of the image analysis.

Author information

Authors and Affiliations

Authors

Corresponding authors

Correspondence to Claudius B. Griesinger or Jonathan F. Ashmore.

Ethics declarations

Competing interests

The authors declare that they have no competing financial interests.

Supplementary information

Supplementary Figure S1

Pharmacology of the calcium current in adult IHCs. The currents showed the properties of a Cav1.3 current with the α1D subunit, that is, non-inactivating L-type current. L-type blockers abolished or reduced stimulus-induced destaining of synaptic ribbons in IHCs in situ indicating that destaining represents vesicular release. (PDF 371 kb)

Supplementary Figure S2

Additional examples of synaptic release from ribbon release sites and accretion of labelled vesicles from cytoplasmic pools at release sites after stimulation. (PDF 1334 kb)

Supplementary Video S1

The video sequence shows increase of fluorescence derived from cytoplasm at a single release site following stimulation of the cell with a 50 s long stimulus train at 40 Hz. The fluorescence increase is interpreted as vesicle accretion from preformed labelled cytoplasmic pools. (AVI 17761 kb)

Supplementary Legends

Supplementary Legends to accompany the Supplementary Figures S1 and S2, and Supplementary Video S1 (DOC 23 kb)

Erratum

Erratum regarding incomplete Supplementary Information uploading to Nature's website for this paper. This correction was made on 03 June 2005. (DOC 19 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Griesinger, C., Richards, C. & Ashmore, J. Fast vesicle replenishment allows indefatigable signalling at the first auditory synapse. Nature 435, 212–215 (2005). https://doi.org/10.1038/nature03567

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature03567

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