The cysteinyl leukotrienes LTC4 and LTD4 are potent mediators of asthma and hypersensitivity. They induce bronchoconstriction, increase microvascular permeability, and are vasoconstrictors of coronary arteries. Their biological effects are transduced by a pair of G-protein coupled receptors, CysLT1 and CysLT2. BayCysLT2 is a potent CysLT2 receptor antagonist that inhibits radioligand binding of LTD4 to CysLT2 and CysLT1 receptor cell lines with IC50 values of 35 and >10,000 nM, respectively. BayCysLT2 concentration-dependently reverses LTC4-stimulated perfusion pressure increase and contractility decrease in isolated Langendorff-perfused guinea pig hearts.
