Airway hyperresponsiveness is also related to a lower release of smooth muscle relaxants, such as adrenaline (Barnes, 1986), vasoactive intestinal peptide (Ben-Jebria et al., 1993) and prostaglandin E2 and I2 (PGE2 and PGI2, respectively) (Van Schoor et al., 2000). The gene discussed is VIP; the disease is airway hyperresponsiveness.