TRPV1 and cough

Cough is one of the most common respiratory complaints and intractable cough remains one of the most distressing and difficult to treat conditions of the lung. It is ironical that the billions of dollars spent worldwide on proprietary over the counter remedies of questionable efficacy¹ for cough exceeds, by orders of magnitude, the money spent on basic cough research. It is therefore not surprising that the cough pharmacopoeia has altered little in the last 50 years, with no important advances over opiate based compounds and cromones. However, basic researchers have not been idle. In this issue of Thorax Trevisani and colleagues² present new information pointing to a causative role for an ion channel called transient receptor potential vanilloid-1 (TRPV1) in cough. They show that the highly selective and potent TRPV1 inhibitor iodo-resiniferatoxin, derived from a plant toxin found in Euphorbia species, strongly suppresses cough induced by inhaled capsaicin or citric acid in conscious guinea pigs, a widely used animal cough model. …