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Multicore Vesicles: Hyperosmolarity and l-DOPA Induce Homotypic Fusion of Dense Core Vesicles

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Abstract

Aim

A fraction of vesicles in cells treated with hypertonic solution exhibit multiple dense cores and this is enhanced by treatment with l-3,4–dihydroxyphenylalanine (l-DOPA). These cells were examined to determine if the multicore vesicles are the product of endocytosis or homotypic fusion.

Methods

Electron microscopy was used to determine the number of multicore vesicles and amperometry was used to examine if the multicore vesicles are a competent fraction of the readily releasable pool.

Results

In this study, we observed that a substantial portion (15.3%) of large dense core vesicles in PC12 cells contained multiple cores in hypertonic saline loaded with l-DOPA, and amperometric measurements show a bimodal distribution of quantal sizes in treated cells.

Conclusions

The results suggest that the multicored vesicles are formed from homotypic fusion of LCDVs prior to exocytosis.

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Fig. 1
Fig. 2

Abbreviations

PC12:

Rat Pheochromocytoma

TEM:

Transmission Electron Microscopy

l-DOPA:

l-3,4-dihydroxyphenylalanine

VMAT:

Vesicular Monoamine Transporter

AL:

Attoliters (10−18l)

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Acknowledgments

The authors would like to acknowledge Missy Hazen and Dr. Gang Ning for assistance with TEM, Dr. Gong Chen for equipment, Paula Powell for software expertise, and Nicole Shakir-Botteri for assistance with cell culture. This work was supported by the National Institutes of Health.

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Authors and Affiliations

  1. Department of Chemistry, The Pennsylvania State University, 104 Chemistry Research Building, University Park, PA, 16802-6300, USA

    Leslie A. Sombers & Andrew G. Ewing

  2. Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, 16802, USA

    Marc M. Maxson

  3. Department of Neuroscience and Anatomy, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA

    Andrew G. Ewing

Authors
  1. Leslie A. Sombers
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  2. Marc M. Maxson
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  3. Andrew G. Ewing
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Correspondence to Andrew G. Ewing.

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Sombers, L.A., Maxson, M.M. & Ewing, A.G. Multicore Vesicles: Hyperosmolarity and l-DOPA Induce Homotypic Fusion of Dense Core Vesicles. Cell Mol Neurobiol 27, 681–685 (2007). https://doi.org/10.1007/s10571-007-9156-y

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  • DOI: https://doi.org/10.1007/s10571-007-9156-y

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