Single cell assay of exocytosis from pancreatic islet B cells

• DOI: 10.1007/bf00378654
• Publication Date: 2004-11-06T17:05:18Z
• Authors: Kevin D. Gillis; Stanley Misler
• Keywords: Electrophysiology; 0301 basic medicine; Islets of Langerhans; 03 medical and health sciences; Cell Membrane; Electric Conductivity; Temperature; Animals; Calcium; Exocytosis

We have measured changes in membrane capacitance (delta Cm) in pancreatic B cells as a single cell assay of insulin secretion. Evidence that depolarization evoked delta Cm reflects exocytosis includes it's voltage, temperature and Ca2+ o dependence. Decreases in Cm, presumably reflecting endocytosis, occur on a variable time scale. Two features that make B cells unique among excitable cells are the large magnitude of delta Cm, when normalized to Ca2+ current, and the rapid "fatigue" of the response for even minimal stimulation, perhaps due to the depletion of a readily releasable pool of vesicles.