Natural relaxant may cure asthma, study says

A NATURAL relaxant that opens the airways may offer a new treatment for asthma, researchers said yesterday.

The compound, nitrosoglutathione (GSNO), is deficient in asthmatics.

Scientists in the US found that mice with raised GSNO levels were less susceptible to the disease.

Research from the Duke University Medical Centre in Durham suggests drugs that increase GSNO levels could offer a new approach to treating asthma.

GSNO is a molecule in the nitric oxide (NO) family. Research suggested NO might play a role in regulating the dilation of the airways. The exhaled breath of asthma patients contains elevated levels of nitric oxide.

Recent evidence from the Duke group indicated a family of NO-carrying molecules called S-nitrosothiols (SNOs) might be necessary for nitric oxide to function in the body.

Researchers looked at the airway responses of normal mice and genetically modified mice lacking an enzyme called GSNO reductase. The enzyme governs GSNO levels in many tissues, including the lungs.

Normal mice prone to asthma had higher GSNO reductase levels, which lowered concentrations of lung GSNO. Mice lacking the enzyme had more GSNO, and were protected from airway hyper-reactivity that makes breathing difficult.