Medical paper says 'Fart gas' (Hydrogen Sulfide) controls blood pressure

Anyone with a nose knows the rotten-egg odor of hydrogen sulfide, a gas generated by bacteria living in the human colon. Now an international team of scientists has discovered that cells inside the blood vessels of mice — as well as in people, no doubt — naturally make the gassy stuff, and that it controls blood pressure.

Having discovered that hydrogen sulfide, or H2S, is produced in the thin, endothelial lining of blood vessels, the researchers, including scientists from Johns Hopkins, now report in Science that H2S regulates blood pressure by relaxing blood vessels. As the newest member of a family of so-called gasotransmitters, this messenger molecule is akin in function, if not form, to chemical signals like nitric oxide, dopamine and acetylcholine that relay signals between nerve cells and excite or put the brakes on mind-brain activities.

http://www.sciencedaily.com/releases/2008/10/081023144053.htm

This is of interest because normally the smelly compounds discussed that are likely to cause fecal body odor or other bloodborne odors are (in terms of the systemic bloodstream) exogenous (externally produced. for instance from the intestine, which is actually outside our systemic system. The intestine is physically a long pipe.). In this case the smelly chemical (Hydrogen Sulfide: H2S) is endogenously produced (within the internal system).

This would be awkward since external chemicals (e.g. H2S generated by bacteria in the colon) can hopefully be eradicated/avoided etc, but internally produced ones (for instance gasotransmitters), we don't have much control over. Only time will tell how significant gasotransmitters are.