Acetylcholinesterase Inhibitor (ACHEI)
An acetylcholinesterase inhibitor (ACHEI, also called cholinesterase inhibitor) is a drug that prevents the enzyme acetylcholinesterase (AChE) from "turning off" the activation of muscles triggered by acetylcholine (ACh).
When acetylcholine activates a muscle, acetylcholinesterase comes into play to "deactivate" it so the muscle can once again relax. It does this by halting the signal traveling between a nerve cell and muscle cell. Substances that inhibit that action include some snake venoms, nerve agents or neurotoxins, such as sarin and some pesticides.