Hideo Kimura
Editor
2013
Hydrogen sulfide (H2S) is a toxic gas that emits an unpleasant smell like rotten eggs. About 20 years ago, the mere presence of a pungent gas was considered as a physiological mediator. Following the discovery of endogenous sulfide in the mammalian brain, we found that H2S is produced by the enzyme cystathionine b-synthase (CBS) and that it functions as a neuromodulator by enhancing the activity of neurotransmitter receptors in the brain. We found another H2S-producing enzyme called cystathionine g-lyase (CSE) in tissues, including vasculature. Another interesting observation was that H2S could function as a smooth muscle
relaxant. Although these enzymes were known to produce H2S in vitro, H2S was considered as a by-product of the metabolic pathways or as a marker for the evaluation of enzyme activity.
Hydrogen Sulfide and its Therapeutic Applications
