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Updated: May 11, 2026
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Single Cell Measurement of Dopamine Release with Simultaneous Voltage-clamp and Amperometry
Published on: November 21, 2012
Evaluating the diffusion coefficient of dopamine at the cell surface during amperometric detection: disk vs ring
Raphaël Trouillon1, Yuqing Lin, Lisa J Mellander
1Department of Chemistry and Molecular Biology, University of Gothenburg, S-41296, Gothenburg, Sweden.
Analytical Chemistry
|May 28, 2013
Summary
Electrochemical detection of neurotransmitter release during exocytosis was compared using two microelectrodes. A pyrolyzed carbon ring microelectrode revealed slower dopamine diffusion near cells, likely due to glycocalyx interactions.
Area of Science:
- Neuroscience
- Electrochemistry
- Cell Biology
Background:
- Exocytosis releases neurotransmitters, quantifiable via electrochemical methods like amperometry.
- Carbon fiber microelectrodes are standard for detecting these exocytotic events.
- Distinct peak shapes in recordings correlate with exocytosis mechanisms.
Purpose of the Study:
- Compare exocytotic peak shapes from PC12 cells using disk carbon fiber and pyrolyzed carbon ring microelectrodes.
- Analyze diffusion processes near the cell membrane with a novel ring electrode.
- Evaluate dopamine diffusion coefficients at the cell surface.
Main Methods:
- Amperometry using disk carbon fiber microelectrodes.
- Amperometry using a 500 nm thick pyrolyzed carbon ring microelectrode array.
- Quantitative analysis of electrochemical current peaks from PC12 cells.
- Diffusion coefficient calculation.
Main Results:
- Ring microelectrode arrays yielded distorted average peak shapes compared to disk electrodes.
- This distortion indicated increased diffusion pathways near the cell.
- Dopamine diffusion coefficient at the cell surface was up to ten times lower than in free buffer.
- Reduced diffusion is potentially caused by interactions with the glycocalyx.
Conclusions:
- Pyrolyzed carbon ring microelectrodes offer precise analysis of membrane-proximal diffusion.
- Dopamine diffusion near PC12 cells is significantly hindered, suggesting glycocalyx involvement.
- This technique advances understanding of exocytosis and neurotransmitter dynamics.
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