To produce all of these effects in the body, a single compound must be able to affect targets all over the body. Nerve gas1 can do this. First, it has access to all cells in the body because it is distributed throughout the bloodstream to all cells. Second, it acts on specific parts of the nervous system that control almost all of our daily functions. To understand how nerve gas does this, it is helpful to review the organization of the nervous system and discuss its specific target, acetylcholinesterase2, the enzyme3 that destroys the neurotransmitter acetylcholine.
1 a group of very lipophilic compounds (e.g. sarin, tabun, soman) that can exist as a vapor at room temperature. They contain phosphorus groups and bind avidly to acetylcholinesterase to inhibit its activity. The inhibition of acetylcholinesterase causes the accumulation of acetylcholine in all areas of the nervous system, causing excessive muscle contraction followed by paralysis, secretions, seizures and death by respiratory failure.
2 the enzyme that facilitates the hydrolysis (by water) of acetylcholine into choline and acetic acid. It is found near neurons that release acetylcholine.
3 a protein that catalyzes the rate at which a reaction occurs. It binds to one of the reactants (a substrate) to cause a change in the reactant’s structure, facilitating the reaction.