Hydrogen sulfide as a new endogenous gaseous transmitter in the cardiovascular system.

Hydrogen sulfide (H(2)S) is a well-known toxic gas with the smell of rotten eggs. Recent studies have shown that H(2)S is generated in vivo in human and animal organisms and that it participates in many pathophysiological processes. H(2)S is produced endogenously in mammalian tissues from L-cysteine metabolism mainly by 3 enzymes: cystathionine beta-synthetase (CBS), cystathionine gamma-lyase (CSE) and 3-mercaptosulfurtransferase (MST). H(2)S may not only function as a neuromodulator in the central nervous system but it also relaxes gastrointestinal smooth muscles. More importantly, present evidence shows that H(2)S exerts regulatory effects on the pathogenesis of various cardiovascular diseases such as hypertension, pulmonary hypertension, shock and myocardial injury. The genomic basis of cystathioninuria in humans is 2 nonsense and 2 sense mutations in CSE. This review reveals that H(2)S is a new endogenous gaseous transmitter in the cardiovascular system.