Notes: Ricinelaidic acid is a 12-hydroxy fatty acid and an antagonist of leukotriene B4 (LTB4) receptors (Ki = 2 µM in porcine neutrophil membranes).{2361} It inhibits chemotaxis and calcium flux induced by LTB4 (Item No. 20110) in isolated human neutrophils (IC50s = 10 and 7 µM, respectively). Ricinelaidic acid (1 mg/kg, i.v.) inhibits bronchoconstriction induced by LTB4 in rats by 46%.