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Nanoscale Amperometry Reveals that Only a Fraction of Vesicular Serotonin Content is Released During Exocytosis from Beta Cells
Author(s) -
Hatamie Amir,
Ren Lin,
Dou Haiqiang,
Gandasi Nikhil R.,
Rorsman Patrik,
Ewing Andrew
Publication year - 2021
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202015902
Subject(s) - exocytosis , amperometry , vesicle , chemistry , biophysics , serotonin , microbiology and biotechnology , biochemistry , membrane , biology , electrochemistry , receptor , electrode
Recent work has shown that chemical release during the fundamental cellular process of exocytosis in model cell lines is not all‐or‐none. We tested this theory for vesicular release from single pancreatic beta cells. The vesicles in these cells release insulin, but also serotonin, which is detectible with amperometric methods. Traditionally, it is assumed that exocytosis in beta cells is all‐or‐none. Here, we use a multidisciplinary approach involving nanoscale amperometric chemical methods to explore the chemical nature of insulin exocytosis. We amperometrically quantified the number of serotonin molecules stored inside of individual nanoscale vesicles (39 317±1611) in the cell cytoplasm before exocytosis and the number of serotonin molecules released from single cells (13 310±1127) for each stimulated exocytosis event. Thus, beta cells release only one‐third of their granule content, clearly supporting partial release in this system. We discuss these observations in the context of type‐2 diabetes.