anticholinesterase Any substance that inhibits the enzyme cholinesterase, which is responsible for the breakdown of the neurotransmitter acetylcholine at nerve synapses. Anticholinesterases, which include certain drugs, nerve gases, and insecticides, cause a build-up of acetylcholine within the synapses, leading to disruption of nerve and muscle function. In vertebrates, these agents often cause death by paralysing the respiratory muscles. See pesticide.

anticholinesterase (anti-koli-nes-ter-ayz) n. any drug or other substance that inhibits the action of cholinesterase and therefore allows acetylcholine to continue transmitting nerve impulses.