CYSLTR2 and allergic rhinitis: Two G protein–coupled receptors for cysLTs have been characterized and designated as cysteinyl leukotriene receptor 1 (CysLT1) and cysteinyl leukotriene receptor 2 (CysLT2).13,14 CysLT1 mediates bronchoconstriction and proinflammatory effects, including activation and migration of leukocytes.15,16 CysLT1 antagonists, including montelukast, are approved for clinical use in patients with asthma and allergic rhinitis.