Re: Yemen: Anti-government protesters may have been hit with nerve gas, doctors say
Nerve agent
http://en.wikipedia.org/wiki/Nerve_agent
Nerve agents are a class of phosphorus-containing organic chemicals (organophosphates) that disrupt the mechanism by which nerves transfer messages to organs. The disruption is caused by blocking acetylcholinesterase, an enzyme that normally relaxes the activity of acetylcholine, a neurotransmitter.
As chemical weapons, they are classified as weapons of mass destruction by the United Nations according to UN Resolution 687 (passed in April 1991) and their production and stockpiling was outlawed by the Chemical Weapons Convention of 1993; the Chemical Weapons Convention officially took effect on April 29, 1997.
Poisoning by a nerve agent leads to contraction of pupils, profuse salivation, convulsions, involuntary urination and defecation and eventual death by asphyxiation as control is lost over respiratory muscles. Some nerve agents are readily vaporized or aerosolized and the primary portal of entry into the body is the respiratory system. Nerve agents can also be absorbed through the skin, requiring that those likely to be subjected to such agents wear a full body suit in addition to a respirator.
.....
Biological effectsAs their name suggests, nerve agents attack the nervous system of the human body. All such agents function the same way: by interrupting the breakdown of the neurotransmitters that signal muscles to contract, preventing them from relaxing.[citation needed]
Initial symptoms following exposure to nerve agents (like sarin) are a runny nose, tightness in the chest and constriction of the pupils. Soon after, the victim will then have difficulty breathing and will experience nausea and drooling. As the victim continues to lose control of his or her bodily functions, he or she will involuntarily salivate, lacrimate, urinate, defecate and experience gastrointestinal pain and vomiting. Blisters and burning of the eyes and/or lungs may also occur.[1][2] This phase is followed by twitching and jerking and ultimately the victim will become comatose and suffocate as a consequence of convulsive spasms.
The
effects of nerve agents are very long lasting and cumulative (increased by successive exposures) and
survivors of nerve agent poisoning almost invariably suffer chronic neurological damage.[dubious ? discuss]
.