Mice lacking the VIP gene show airway hyperresponsiveness and airway inflammation, partially reversible by VIP.

The mechanisms leading to asthma, and those guarding against it, are yet to be fully defined. The neuropeptide VIP is a cotransmitter, together with nitric oxide (NO), of airway relaxation, and a modulator of immune and inflammatory responses. NO-storing molecules in the lung were recently shown to modulate airway reactivity and were proposed to have a protective role against the disease.

Garlic and its active metabolite allicin produce endothelium- and nitric oxide-dependent relaxation in rat pulmonary arteries.

1. The aims of the present study were to investigate the effects of fresh garlic and one of its active metabolites, allicin, on rat isolated pulmonary arteries (RPA). 2.