Evidence for the formation of a novel nitrosothiol from the gaseous mediators nitric oxide and hydrogen sulphide

Biochem Biophys Res Commun. 2006 Apr 28;343(1):303-10. doi: 10.1016/j.bbrc.2006.02.154. Epub 2006 Mar 6.

Abstract

The gaseous mediators hydrogen sulphide (H2S) and nitric oxide (*NO) are synthesised in the body from L-cysteine and L-arginine, respectively. In the cardiovascular system, *NO is an important regulator of vascular tone and its over- or under-production has been linked to a variety of diseases. The physiological significance of H2S is not yet clear but, like *NO, it exhibits vasodilator activity and may play a part in septic and haemorrhagic shock, hypertension, regulation of cardiac contractility, and in inflammation. To date, there have been no reports of a chemical interaction between H2S and *NO. Here we show that incubation of the H2S donor, sodium hydrosulphide, with a range of *NO donors and *NO gas in vitro leads to the formation of a nitrosothiol molecule as determined by a combination of techniques; electron paramagnetic resonance, amperometry, and measurement of nitrite. We further show that this nitrosothiol did not induce cGMP accumulation in cultured RAW264.7 cells unless *NO was released with Cu2+. Finally, using liver homogenates from LPS treated rats we present evidence for the endogenous formation of this nitrosothiol. These findings provide the first evidence for the formation of a novel nitrosothiol generated by reaction between H2S and *NO. We propose that generation of this nitrosothiol in the body may regulate the physiological effects of both *NO and H2S.

MeSH terms

  • Animals
  • Cells, Cultured
  • Cyclic GMP / metabolism
  • Electron Spin Resonance Spectroscopy
  • Hydrogen Sulfide / metabolism*
  • Lipopolysaccharides / pharmacology
  • Liver / drug effects
  • Liver / metabolism
  • Mice
  • Nitric Oxide / metabolism*
  • Rats
  • S-Nitrosothiols / metabolism*

Substances

  • Lipopolysaccharides
  • S-Nitrosothiols
  • Nitric Oxide
  • Cyclic GMP
  • Hydrogen Sulfide