Hydrogen sulfide (H2S): the new member of gasotransmitter family

Abstract

Recent studies indicate that apart from nitric oxide (NO) and carbon monoxide (CO), hydrogen sulfide (H2S) is the third gaseous mediator in mammals. H2S is synthesized from L-cysteine by either cystathionine β-synthase (CBS) or cystathionine γ-lyase (CSE), vitamin B6-dependent enzymes also involved in homocysteine metabolism. H2S stimulates ATP-sensitive potassium channels (KATP) in vascular smooth muscle cells, neurons, cardiomyocytes and pancreatic β-cells. H2S is involved in neurotransmission, regulation of vascular tone and blood pressure, regulates gastrointestinal motility and secretory function and inhibits insulin secretion. Deficiency of endogenous H2S was observed in various models of arterial and pulmonary hypertension, gastric mucosal injury and liver cirrhosis. Exogenous H2S or its donors decrease blood pressure and reduce vascular hypertrophy in spontaneously hypertensive rats, inhibit neointima formation induced by arterial injury, ameliorate myocardial dysfunction associated with ischemia/reperfusion, and reduce gastric mucosal damage induced by anti-inflammatory drugs. On the other hand, excessive production of H2S may contribute to the pathogenesis of inflammatory diseases, septic shock, cerebral stroke and mental retardation in patients with Down syndrome, and reduction of its production may be of potential therapeutic value in these diseases. Biomedical Reviews 2007; 18: 75-83.