Vasoactive intestinal peptide causes bronchodilatation and protects against histamine-induced bronchoconstriction in asthmatic subjects.

Vasoactive intestinal peptide (VIP) caused significant bronchodilatation in seven asthmatic volunteers when given intravenously at the rate of 6 pmol/kg/min for 15 min during a double-blind study. Tachycardia and cutaneous flushing were observed during the infusion. VIP also ameliorated histamine-induced bronchoconstriction in all subjects. VIP may be an important natural bronchodilator in man and this has implications for the pharmacotherapy of asthma.