Nerve gas

Nerve agents are a class of phosphorus-containing organic chemicals (organophosphates) that disrupt the mechanisms by which nerves transfer messages to organs. The disruption is caused by blocking acetylcholinesterase, an enzyme that catalyzes the breakdown of acetylcholine, a neurotransmitter.

Poisoning by a nerve agent leads to contraction of pupils, profuse salivation, convulsions, involuntary urination and defecation, and death by asphyxiation due to a loss of control of the 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.

As their name suggests, nerve agents attack the nervous system of the human body. All such agents function the same way: by inhibiting the enzyme acetylcholinesterase, which is responsible for the breakdown of acetylcholine (ACh) in the synapse. ACh gives the signal for muscles to contract, thus, if it cannot be broken down, muscles are prevented from relaxing.

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 their bodily functions, they will involuntarily salivate, lacrimate, urinate, defecate, and experience gastrointestinal pain and vomiting. Blisters and burning of the eyes and/or lungs may also occur. This phase is followed by initially myoclonic jerks followed by status epilepticus. Death then comes via complete respiratory depression, most likely via the excessive peripheral activity at the neuromuscular junction of the diaphragm.

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