The effects of calcium2+ and magnesium2+ on the electrophoretic mobility of chromaffin granules measured by electrophoretic light scattering.
Electrophoretic light scattering was used to determine the electrophoretic mobility distributions of isolated bovine adrenal chromaffin granules as a function of divalent metal ion concentrations. Changes in the electrophoretic mobility reflected changes in the surface charge density of the granules. Ca2+ and Mg2+ (0.10--2.0 mM) were equally effective in reducing the electrophoretic mobilities. These findings are consistent with recent studies of the binding of Ca2+ and Mg2+ to the surface of chromaffin granules and are further evidence that the specific role of Ca2+ in exocytosis is due to effects other than the ability of Ca2+ to decrease the electrostatic repulsion between negatively charged membranes.
D000313:Adrenal Medulla / Q000648:ultrastructure; D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002417:Cattle; D002837:Chromaffin Granules / Q000187:drug effects / Q000648:ultrastructure*; D002838:Chromaffin System / Q000648:ultrastructure*; D004586:Electrophoresis; D008027:Light; D008274:Magnesium / Q000494:pharmacology*; D012542:Scattering, Radiation
D008274:Magnesium; D002118:Calcium