Among the inflammatory mediators involved in asthma, cysteinyl-LTs seem to play a key role in the bronchoconstrictor response to allergen [15-17] through activation of CysLT1R. Though preferentially coupled to Gq/11-protein, constitutively expressed CysLT1 also activates pertussis toxin (PTX)-sensitive and -insensitive G-proteins [43,44]. This evidence concerns the gene CYSLTR1 and asthma.