R 59-022 (DKGI-I) is a DGK inhibitor (IC50: 2.8 µM). R 59-022 inhibits the phosphorylation of OAG to OAPA. R 59-022 is a 5-HT Receptor antagonist, and activates protein kinase C (PKC). R 59-022 potentiates thrombin-induced diacylglycerol production in platelets and inhibits phosphatidic acid production in neutrophils[1][2][3][4].