Nitric Oxide
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Contents |
Introduction
- A colorless gas & a free radical. NO reacts rapidly with oxygen to form nitrogen oxides, which ultimately convert to nitrite (NO2-) & nitrate (NO3-).
* NO + O2 -> NO2 + N2O3 + N2O2 -> NO2- + NO3-
- It is a gaseous mediator of cell to cell communication & a potent vasodilator. It is formed from L-arginine by:
- a constitutuve NO synthase (NO synthase-1 or NO synthase-3) in
- brain
- peripheral nerves
- endothelium (NO-synthase-3)
- bone
- granulocytes
- pancreatic beta cells
- an inducible NO synthase (NO synthase-2) in
- Kupffer cells
- macrophages
- smooth muscle
- NO activates soluble guanylate cyclase.
- It mediates penile erection.
- In the immune system, macrophages use NO as a cytotoxic agent.
- Insufficient NO may contribute to hypertension.
- Free NO in the circulation is rapidly reduced by Fe+2 of hemoglobin.
- Nitric oxide covalently binds to cysteine residues of proteins resulting in S-nitrosylated derivatives. [2,3] S-nitrosylation is reversible.
- Targets of S-nitrosylation include:
- Na+ pump
- Na+ K+ ATPase
- alpha tubulin
- NMDA receptor
- GAPDH*
- * S-nitrosylation of GAPDH triggers nuclear translocation via binding to Siah1. Nitrosylated GAPDH stablizes Siah1, an E3-ubiquitin ligage that mediates proteolysis of nuclear proteins leading to apoptosis.
More General Terms
Additional Terms
Internet Database
PubChem: 945
PubChem: 84878
PubChem: 145068
PubChem: 3001380
References
- Stedman's Medical Dictionary 27th ed, Williams & Wilkins, Baltimore, 1999
- Tidball J, 9th Annual UCLA Research Conference on Aging, June 17, 2004 (conference speaker)
- Sedlak TW, Snyder SH. Messenger molecules and cell death: therapeutic implications. JAMA. 2006 Jan 4;295(1):81-9. PMID: [1]
- National Guideline Clearinghouse NIH Consensus Development Conference statement on inhaled nitric oxide therapy for premature infants. National Institutes of Health Consensus Development Conference ngc-guideline: [2]
