1992 Volume 41 Issue 12 Pages 1710-1716
We investigated the signal transduction of serotonin secretion by stimulation with DNP-Ascaris antigen or ionomycin in rat basophilic leukemia cells (RBL-2H3). The modes of action of antigen and ionomycin for serotonin secretion were shown to be similar. The treatment of cells with antigen resulted in increased tyrosine phosphorylation of 105 and 72 KDa proteins, in particular, the tyrosine phosphorylation of 72 KDa protein seemed to correlate with serotonin secretion. Furthermore, we observed that antigen stimulation caused a marked increase in inositol polyphosphates production, which derived from the tyrosine phosphorylation of phospholipase C-γ in RBL-2H3 cells. On the other hand, treatment with ionomycin also resulted in an increase in tyrosine phosphorylation of 72KDa protein, but did not induce inositol polyphosphates production. These results suggested that the activation of tyrosine kinase may be related to serotonin secretion, and that intracellular Ca^<2+> increase may also play an important role in this activation.
