Role of Calcium in Exocytosis Induced by Hypotonic Swelling
Abstract: We studied the influence of Ca2+ on exocytosis induced by hypotonic shock using the fluorescent dyes acridine orange FM1-43 and FM2-10. It was shown using acridine orange that lowering osmolarity to 230 mOsm/L induces exocytosis both in calcium-containing and calcium-free media. By contrast, we were able to demonstrate calcium dependence of exocytosis using styryl dyes. Lowering osmolarity leads to an increase of neurotransmitter release in a calcium-independent manner. Thus, our data suggest that hypotonic swelling induces calcium-independent exocytosis. Calcium influx mediated by stretch channels is able to switch mode of exocytosis from kiss and run to full fusion.
exocytosis hypotonic swelling acridine orange kiss and run synaptosomes fm2-10