Evidence Confirms Link Between H₂S And Blood Pressure

New evidence supports the hypothesis that hydrogen sulfide—in addition to nitric oxide—helps regulate blood pressure (Science 2008, 322, 587). To assess the role of the chemical, famous for its rotten-egg stench, Rui Wang of Lakehead University, in Thunder Bay, Ontario, and colleagues created mutant mice that were unable to produce cystathionine γ-lyase (CSE), an enzyme suspected of forming H₂S in the body. The mice produced significantly less H₂S in their cardiovascular tissue and had higher blood pressure than normal mice. Injections of NaHS, an H₂S donor, temporarily reduced blood pressure in the mutant mice. In other experiments the researchers showed that calcium and calmodulin stimulate CSE's production of H₂S. The compound then relaxes blood vessels, thereby lowering blood pressure. The researchers note that hydrogen sulfide's effect is comparable with that of NO. They suggest that a pharmacological therapy that raises H₂S production could be used as an alternative approach for treating high blood pressure.