Single cell assay of exocytosis from pancreatic islet B cells.
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.
Gillis
K D
KD
Department of Medicine (Jewish Hospital), Washington University, St. Louis, MO 63110.
Misler
S
S
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002462:Cell Membrane / Q000502:physiology; D004553:Electric Conductivity; D004594:Electrophysiology; D005089:Exocytosis; D007515:Islets of Langerhans / Q000502:physiology*; D013696:Temperature
D002118:Calcium