Cholinesterase inhibitors

Biological: Behavioural genetics · Evolutionary psychology · Neuroanatomy · Neurochemistry · Neuroendocrinology · Neuroscience · Psychoneuroimmunology · Physiological Psychology · Psychopharmacology (Index, Outline)

An acetylcholinesterase inhibitor or anti-cholinesterase is a chemical that inhibits the cholinesterase enzyme from breaking down acetylcholine, so increasing both the level and duration of action of the neurotransmitter acetylcholine.

Uses[edit | edit source]

Acetylcholinesterase inhibitors:

occur naturally as venoms and poisons
are used as weapons in the form of nerve agents
are used medicinally:
- to treat myasthenia gravis. In myasthenia gravis, they are used to increase neuromuscular transmission.
- to treat Alzheimer's disease
- as an antidote to anticholinergic poisoning

Examples[edit | edit source]

reversible inhibitor[edit | edit source]

Compounds which function as reversible competitive or noncompetitive inhibitors of cholinesterase are those most likely to have therapeutic uses. These include:

Organophosphates
- metrifonate
Carbamates
Phenanthrine derivatives
- galanthamine
Piperidines
- donepezil, also known as E2020
Tacrine, also known as tetrahydroaminoacridine (THA')
Edrophonium
Phenothiazines

Comparison table[edit | edit source]

Comparison of reversible acetylcholinesterase inhibitors
Inhibitor	Duration^[1]	Main site of action^[1]	Clinical use^[1]	Adverse effects^[1]
edrophonium	short	neuromuscular junction	diagnosis of myasthenia gravis
neostigmine	medium	neuromuscular junction	reverse neuromuscular block (intravenously) treat myasthenia gravis (orally)	visceral
physiostigmine	medium	postganglionic parasympathetic	treat glaucoma (eye drops)
pyridostigmine	medium	neuromuscular junction	treat myasthenia gravis (orally)
dyflos	long	postganglionic parasympathetic	historically to treat glaucoma (eye drops)	toxic
ecothiopate	long	postganglionic parasympathetic	treat glaucoma (eye drops)	systemic effects
parathion	long	none	toxic

quasi-irreversible inhibitor[edit | edit source]

Compounds which function as quasi-irreversible inhibitors of cholinesterase are those most likely to have use as chemical weapons or pesticides. These include:

Organophosphates
- echothiophate
- diisopropyl fluorophosphate
- cyclosarin
- sarin
- soman
- tabun
- VX
- VE
- VG
- VM
- diazinon
- malathion
- parathion
Carbamates
- aldicarb
- bendiocarb
- bufencarb
- carbaryl
- carbendazim
- carbetamide
- carbofuran
- chlorbufam
- chloropropham
- ethiofencarb
- formetanate
- methiocarb
- methomyl
- oxamyl
- phenmedipham
- pinmicarb
- pirimicarb
- propamocarb
- propham
- propoxur

Natural Compounds (Supplements)[edit | edit source]

Huperzine A

Effects[edit | edit source]

Some major effects of anticholinesterases:

Actions on the autonomic nervous system, that is parasympathetic nervous system will cause bradycardia, hypotension, hypersecretion, bronchoconstriction, GI tract hypermotility, and decrease intraocular pressure.
SLUD syndrome.
Actions on the neuromuscular junction will result in prolonged muscle contraction.

References[edit | edit source]

↑ ^1.0 ^1.1 ^1.2 ^1.3 Unless else specified n boxes, then ref is:Rang, H. P. (2003). Pharmacology, Edinburgh: Churchill Livingstone. Page 156

External links[edit | edit source]

MeSH Acetylcholinesterase+inhibitors

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[Rang156unless-1] 1.0 ^1.1 ^1.2 ^1.3 Unless else specified n boxes, then ref is:Rang, H. P. (2003). Pharmacology, Edinburgh: Churchill Livingstone. Page 156

[1]

v·d·e Pharmacology: enzyme inhibition
Class	Competitive inhibition - Uncompetitive inhibition - Non-competitive inhibition - Suicide inhibition - Mixed inhibition
Substrate	Acetylcholinesterase inhibitors - Aromatase inhibitors - Carbonic anhydrase inhibitors - Integrase inhibitor - Kinase inhibitors - Lipoxygenase inhibitor - Monoamine oxidase inhibitors - Reverse transcriptase inhibitors - Phosphodiesterase inhibitors - Protease inhibitors (ACE inhibitor, Trypsin inhibitor)

v·d·e Anticholinesterases (N06DA, N07AA)
Carbamates	Ambenonium - Demecarium - Stigmine (Neostigmine, Physostigmine, Pyridostigmine, Rivastigmine)
Other	Galantamine - Metrifonate - Donepezil - Tacrine - Edrophonium

v·d·e Psychoanaleptics: anti-dementia drugs (N06D)
Anticholinesterases	Tacrine - Donepezil - Rivastigmine - Galantamine
Other	NMDA receptor antagonist (Memantine) - Ginkgo biloba

v·d·e Parasympathomimetics (N07A)
Anticholinesterases	Stigmine (Neostigmine, Pyridostigmine, Distigmine) - Ambenonium
Choline esters	Carbachol - Bethanechol
Other parasympathomimetics	Pilocarpine - Choline alfoscerate