Movement of calcium ions and release of histamine from rat mast cells.

Rat mast cells were stimulated for histamine release in a medium containing radioactive calcium, by band 2 protein (B2) and compound 48/80. It was found that a significant amount of extracellular calcium was taken up by the stimulated cells. When the histamine release process was divided into two stages by activating the cells at 0 degrees C and then washing them prior to suspending them in Tyrode's solution at 37 degrees C, it was found that calcium uptake by the cells took place at the release stage. This suggests that calcium entry into the cells occurs subsequent to the activation stage. Inhibition of histamine release by 2-deoxyglucose (2-DG) and 2,4-dinitrophenol (DNP) also inhibited the calcium influx into the cells. The present studies also suggest that calcium does not diffuse into the cells as a result of degranulation. These findings have been discussed in relation to the mobilization of intracellular calcium.