Fast calcium transients in rat peritoneal mast cells are not sufficient to trigger exocytosis.

摘要: The calcium concentration, [Ca]i, in single rat peritoneal mast cells was measured by means of the new Ca indicator dye fura-2. Upon stimulation with antigen or compound 48/80, [Ca]i rose for seconds to values greater than 5 microM. These transients did not depend on presence extracellular Ca, and they sometimes occurred spontaneously, especially exogenous phosphatidylserine. Calcium necessarily lead degranulation. Degranulation usually during periods somewhat elevated [Ca] (0.5-1 microM) following but observed at less equal 250 nM. We found no evidence that an antigen-induced influx is required