How Nerve Agents Work

Nerve-agent poisoning is caused when the action of the enzyme acetyl cholinesterase is blocked. The normal function of acetyl cholinesterase is to break down (hydrolyze) the chemical acetylcholine. Acetylcholine is a neurotransmitter, or messenger chemical.

Nerve paths, which are divided into sections with gaps between the nerve endings and between the nerve ending and the target organ, are used to pass a command from the central nervous system to various organs.

These gaps are crossed by acetylcholine, the messenger, which relays the command to the next step and finally to the target. Under normal conditions, when the required action at each step is completed, the acetylcholine is broken down by the acetyl cholinesterase, thus stopping the action.

When a nerve agent inhibits the acetyl cholinesterase, this enzyme cannot perform its normal function of breaking down the acetylcholine. Acetylcholine then accumulates along the nerve path, and the target organ's action continues uncontrolled. Muscles become hyperactive and twitch uncontrollably, and glands secrete copiously.