Effect of a Novel Antiallergic Drug, Pemirolast, on Activation of Rat Peritoneal Mast Cells: Inhibition of Exocytotic Response and Membrane Phospholipid Turnover

摘要

The effects of a potent antiallergic drug, pemirolast (TBX), on activation of signal-transducing phospholipase C and A2, were examined in rat peritoneal mast cells. TBX at concentrations between 10––/sup>7 and 10––5 g/ml effectively inhibited degranulation in response to both antigen and compound 48/80. At the same concentrations the drug markedly suppressed the formation of 1,2-diacylglycerol and phosphatidic acid, and the decrease in phosphatidylinositol, suggesting the prevention of phospholipase C activation. The blockade of phospholipase A2 was suggested by the decrease in agonists-induced arachidonic acid liberation. These results indicate that TBX may exert its inhibitory effects on mast cells, at least in part, by preventing the activation of signal-transducing phospho