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The secretory granule matrix-electrolyte interface: a homologue of the p-n rectifying junction.

Publication ,  Journal Article
Marszalek, PE; Markin, VS; Tanaka, T; Kawaguchi, H; Fernandez, JM
Published in: Biophysical journal
October 1995

When placed at the tip of a glass micropipette electrode the polymeric matrix of the secretory granule behaves like a diode. The measured current was 100-fold greater at negative potentials compared to positive potentials, and up to sixfold greater than that measured with the pipette alone. By manipulating the geometry of the electric field we show that these electrical properties result from focusing an electric field at the gel-electrolyte interface. We also show, by using pulsed-laser imaging with fluorescein as the ionic probe, that there is a rapid accumulation and depletion of ions at the gel-electrolyte interface. A voltage pulse of -9 V applied to the gel caused a severalfold increase in the fluorescence intensity within 5 ms. This correlated with an increase in the measured current (approximately 1 microA). In contrast, within 5 ms of applying +9 V we recorded a decrease in the fluorescence intensity, which paralleled the twofold decrease in the measured current. This is similar to a p-n junction where an applied voltage causes the accumulation and depletion of charge carriers. Using synthetic gels (diameter 3-6 microns) with different charge characteristics we observed no rectification of the current with neutral gels and confirmed that rectification and amplification of the current were dependent on the fixed charge within a gel. In addition, we modeled the conduction at the gel-electrolyte interface using the Nernst-Planck electrodiffusion equation and accurately fitted the experimental current-voltage relationships. This study provides some insight into how biological interfaces may function. For example, we suggest that neurotransmitter release during exocytosis could be regulated by voltage-induced accumulation and depletion of ions at the interface between the secretory granule and the fusion pore.

Duke Scholars

Published In

Biophysical journal

DOI

EISSN

1542-0086

ISSN

0006-3495

Publication Date

October 1995

Volume

69

Issue

4

Start / End Page

1218 / 1229

Related Subject Headings

  • Models, Theoretical
  • Mice, Mutant Strains
  • Mice
  • Membrane Potentials
  • Mathematics
  • Mast Cells
  • Lasers
  • Intracellular Membranes
  • Electrophysiology
  • Electrolytes
 

Citation

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ICMJE
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Marszalek, P. E., Markin, V. S., Tanaka, T., Kawaguchi, H., & Fernandez, J. M. (1995). The secretory granule matrix-electrolyte interface: a homologue of the p-n rectifying junction. Biophysical Journal, 69(4), 1218–1229. https://doi.org/10.1016/s0006-3495(95)80004-4
Marszalek, P. E., V. S. Markin, T. Tanaka, H. Kawaguchi, and J. M. Fernandez. “The secretory granule matrix-electrolyte interface: a homologue of the p-n rectifying junction.Biophysical Journal 69, no. 4 (October 1995): 1218–29. https://doi.org/10.1016/s0006-3495(95)80004-4.
Marszalek PE, Markin VS, Tanaka T, Kawaguchi H, Fernandez JM. The secretory granule matrix-electrolyte interface: a homologue of the p-n rectifying junction. Biophysical journal. 1995 Oct;69(4):1218–29.
Marszalek, P. E., et al. “The secretory granule matrix-electrolyte interface: a homologue of the p-n rectifying junction.Biophysical Journal, vol. 69, no. 4, Oct. 1995, pp. 1218–29. Epmc, doi:10.1016/s0006-3495(95)80004-4.
Marszalek PE, Markin VS, Tanaka T, Kawaguchi H, Fernandez JM. The secretory granule matrix-electrolyte interface: a homologue of the p-n rectifying junction. Biophysical journal. 1995 Oct;69(4):1218–1229.
Journal cover image

Published In

Biophysical journal

DOI

EISSN

1542-0086

ISSN

0006-3495

Publication Date

October 1995

Volume

69

Issue

4

Start / End Page

1218 / 1229

Related Subject Headings

  • Models, Theoretical
  • Mice, Mutant Strains
  • Mice
  • Membrane Potentials
  • Mathematics
  • Mast Cells
  • Lasers
  • Intracellular Membranes
  • Electrophysiology
  • Electrolytes