US researchers say hydrogen sulfide, known for its bad smell is important for regulating our blood pressure. According to the study published in Science, researchers at John Hopkins University, in Maryland found that hydrogen sulfide; a toxic gas responsible for the foul odor of flatulence is also produced by an enzyme called CSE in the thin lining of the blood vessels. This regulates blood pressure by relaxing the blood vessels.

Guangdong Yang, PhD, of the University of Saskatchewan and Lakehead University in Canada, and colleagues examined two groups of mice in the study. One group of mice was normal while the second group of mice had been engineered to not have CSE, an enzyme long suspected of making hydrogen sulfide.

The hydrogen sulfide levels were measured in both groups and the ones without CSE had much lower levels of hydrogen sulfide. This provided evidence that mammals make hydrogen sulfide in tissues using CSE. The CSE-deficient mice also had blood pressure counts that were 20% higher than the normal mice, comparable to serious hypertension in humans. When the mice were administered methacholine, a drug which relaxes normal blood vessels there was no difference which indicated that the gas was responsible for the relaxation.

Co-author and Johns Hopkins neuroscientist Solomon H. Snyder, MD said, "Now that we know hydrogen sulfide's role in regulating blood pressure, it may be possible to design drug therapies that enhance its formation as an alternative to the current methods of treatment for hypertension."

Professor Amrita Ahluwalia, an expert in vascular pharmacology at Barts and The London Medical School, said, "This study shows that smelly hydrogen sulphide is also likely to have a role in regulating blood pressure and it will be a bit of an impetus for scientists to develop more specific tools to work out what's going on. We know hydrogen sulphide is not good for us at high levels but it seems that at the lower levels in the body it is essential."

Dr Allan MacDonald, a reader in pharmacology at Glasgow Caledonian University, said: "Treatments based on hydrogen sulphide could become important in a variety of cardiovascular diseases," he said.

The study's authors said that new drugs which used hydrogen sulfide could be developed to treat hypertension in humans.