Acetylcholine, deactivation acetylcholinesterase

Acetylcholine, deactivation by acetylcholinesterase, 469-470 Acetylcholinesterase, inhibition of acetylcholine, 469-470,471/... 

The physiological activity of acetylcholine relies on local release, stimulation of the receptor, then rapid hydrolysis (deacetylation) by acetylcholinesterase, which results in deactivation. The indole alkaloid physostigmine, from the West African calabar bean, and the relatively simple synthetic compound pyridostigmine, which has a more obvious relationship to choline, are reversible inhibitors of acetylcholinesterase. Controlled inhibition of the enzyme by such drugs, which results in a build-up of ACh, is useful in conditions such as myasthenia gravis, a muscle weakness, which is caused by insufficient production of ACh. 

Organophosphorus and carbamate insecticides are the two classes of anticholinesterase insecticides. All anticholinesterases inhibit nervous tissue acetylcholinesterase, the enzyme that deactivates the neurotransmitter acetylcholine (Ecobichon 1996). Poisoning causes accumulation of acetylcholine in the synaptic cleft, resulting in continuous electrical stimulation (Chambers 1992 Costa 1988). Described best by Chambers (1992), the mechanism of acute symptoms of poisoning occurs through three pathways ... 

Choline esters are simply choline bound to an acetyl derivative by an ester bond. The ester bond of acetylcholine and related drugs is hydrolyzed by enzymes known as cholinesterases (e.g., acetylcholinesterase). Choline esters are more or less sensitive to cholinesterase deactivation depending on their chemical structure. 

Acetylcholine (ACh) is a natural neurotransmitter. After release from presynaptic nerve terminals and interaction with postsynaptic acetylcholine receptors, it is deactivated by acetylcholinesterase (AChE), which... 

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