Detection of exocytosis at individual pancreatic beta cells by amperometry at a chemically modified microelectrode

Amperometry at a carbon fiber microelectrode modified with a composite of ruthenium oxide and cyanoruthenate was used to monitor chemical secretions of single pancreatic beta cells from rats and humans. When the insulin secretagogues glucose, tolbutamide, and K+ were applied to the cell, a series of...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 1995-10, Vol.92 (21), p.9608-9612
Main Authors: Huang, L, Shen, H, Atkinson, M A, Kennedy, R T
Format: Article
Language:English
Subjects:
Anatomy & physiology
Animals
Biochemistry
Calcium - pharmacology
Cells, Cultured
Cellular biology
Chromatography, High Pressure Liquid
Electric Conductivity
Electrophysiology - instrumentation
Exocytosis - drug effects
Exocytosis - physiology
Humans
Insulin - metabolism
Insulin Secretion
Islets of Langerhans - cytology
Islets of Langerhans - drug effects
Islets of Langerhans - physiology
Microelectrodes
Rats
Rodents
Species Specificity
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Summary:Amperometry at a carbon fiber microelectrode modified with a composite of ruthenium oxide and cyanoruthenate was used to monitor chemical secretions of single pancreatic beta cells from rats and humans. When the insulin secretagogues glucose, tolbutamide, and K+ were applied to the cell, a series of randomly occurring current spikes was observed. The current spikes were shown to be due to the detection of chemical substances secreted from the cell. Chromatography showed that the primary secreted substance detected by the electrode was insulin. The current spikes were strongly dependent on external Ca2+, had an average area that was independent of the stimulation method, and had an area distribution which corresponded to the distribution of vesicle sizes in beta cells. It was concluded that the spikes were due to the detection of concentration pulses of insulin secreted by exocytosis.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.92.21.9608