Effect of 12-O-tetradecanoylphorbol-13-acetate (TPA) on substance P-induced histamine release from rat peritoneal mast cells

Abstract

12-O-tetradecanoylphorbol-13-acetate (TPA, 1 to 30 ng/ml) produced a dose-related inhibition of substance P (SP)-induced histamine release from rat peritoneal mast cells. TPA itself induced some histamine release over this concentration range (maximum release about 20% of total). Maximum inhibition of SP-induced release by TPA required preincubation with TPA for at least 10 min. The inhibitory action of TPA was observed in the absence as well as in the presence of extracellular calcium (0.4 mM). Inhibition of diacylglycerol kinase by R 59022 or of diacylglycerol lipase by RHC 80267 reduced SP-induced histamine release. Oleolylacetylglycerol (OAG, 50 microM) inhibited histamine release induced by SP but was less potent than TPA. It is concluded that protein kinase C activation in rat peritoneal mast cells is associated with inhibition of SP-induced histamine release.