Signaling Pathways

Author: Gianpiero Pescarmona
Date: 28/04/2011


Gasotransmitters are a group of gaseous mediators that include nitric oxide, hydrogen sulfide and carbon monoxide


Hydrogen Sulfide: Neurophysiology and Neuropathology 2011

Hydrogen sulfide (H2S) was known to be a toxic gas and an environmental hazard for many decades. However, it is now recognized that H2S may serve as a gaseous mediator that is endogenously produced to influence biological functions in mammalian. The past decade has seen an exponential growth of scientific interest in the physiological and pathological significance of H2S especially with respect to its role in the central nervous system and the cardiovascular system. In the central nervous system, H2S facilitates long-term potentiation and regulates intracellular calcium concentration and pH level in brain cells. Intriguingly, H2S produces antioxidant, anti-inflammatory, and antiapoptotic effects that may have relevance to neurodegenerative disorders. Abnormal generation and metabolism of H2S have been reported in the pathogenesis of ischemic stroke, Alzheimer's disease, Parkinson's disease, and recurrent febrile seizure. Exogenously applied H2S is demonstrated to have value for the treatment of febrile seizure and Parkinson's disease. This article presents an overview of current knowledge of H2S in relation to brain functions, with a special emphasis on its neuroprotective effects and the underlying cellular and molecular mechanisms.

Gaso-transmitter hydrogen sulphide: potential new target in pharmacotherapy. 2010 Indian J Exp Biol. 2010 Nov;48(11):1069-77.
Research in the last two decades has transformed the way hydrogen sulphide (H2S) is perceived from a noxious gas to a gaso-transmitter with a vast potential in pharmacotherapy. H2S is synthesized in various body-systems using the enzymes cystathionine beta-synthase and cystathionine gamma-lyase; either of these being the predominat enzyme in a particular system. H2S may be one of the physiological modulators of blood pressure in humans. The gas relaxes the vascular smooth muscle cells by opening up K(ATP) channels. Moreover, it suppresses the proliferation of vascular smooth muscle cells. H2S may also be contributing in the protection afforded by ischaemia-preconditioning. Testosterone is thought to be responsible for the higher central nervous system level of H2S in males. In the central nervous system, H2S is implicated in Alzheimer's disease, epilepsy, stroke and Down's syndrome. Insulin secretion is associated with a decrease in the H2S levels. Raised H2S is detrimental in acute pancreatitis as well as in septic shock. Recently, H2S-releasing derivatives of certain drugs have shown promise in protection against gastric ulcer and in inflammatory bowel disease. The beneficial effects of certain sulphur containing herbs like ginseng and garlic may be mediated via H2S. In future, development of specific drugs modulating H2S levels may prove beneficial in varied disorders.

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