Acetylcholinesterase inhibitor
From Wikipedia, the free encyclopedia
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.
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[edit] Uses
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
[edit] Examples
[edit] Reversible inhibitor
Compounds which function as reversible competitive or noncompetitive inhibitors of cholinesterase are those most likely to have therapeutic uses. These include:
- Organophosphates
- Carbamates
- Physostigmine
- Neostigmine
- Pyridostigmine
- Ambenonium
- Demarcarium
- Rivastigmine
- Phenanthrine derivatives
- Piperidines
- Donepezil, also known as E2020
- Tacrine, also known as tetrahydroaminoacridine (THA')
- Edrophonium
- Phenothiazines
[edit] Comparison table
| Inhibitor | Duration[1] | Main site of action[1] | Clinical use[1] | Adverse effects[1] |
|---|---|---|---|---|
| Edrophonium | short (10 min.) | neuromuscular junction | diagnosis of myasthenia gravis | |
| Neostigmine | medium (1-2 hrs.) | neuromuscular junction |
|
visceral |
| Physiostigmine | medium (0.5-5 hrs.) | postganglionic parasympathetic | treat glaucoma (eye drops) | |
| Pyridostigmine | medium (2-3 hrs.) | neuromuscular junction |
|
|
| 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 |
[edit] Quasi-irreversible inhibitor
Compounds which function as quasi-irreversible inhibitors of cholinesterase are those most likely to have use as chemical weapons or pesticides. These include:
- Organophosphates
- Carbamates
- Aldicarb
- Bendiocarb
- Bufencarb
- Carbaryl
- Carbendazim
- Carbetamide
- Carbofuran
- Chlorbufam
- Chloropropham
- Ethiofencarb
- Formetanate
- Methiocarb
- Methomyl
- Oxamyl
- Phenmedipham
- Pinmicarb
- Pirimicarb
- Propamocarb
- Propham
- Propoxur
[edit] Natural Compounds (Supplements)
[edit] Effects
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.
[edit] See also
[edit] References
- ^ a b c d Unless else specified n boxes, then ref is:Rang, H. P. (2003). Pharmacology. Edinburgh: Churchill Livingstone. ISBN 0-443-07145-4. Page 156
[edit] External links
- ATSDR Case Studies in Environmental Medicine: Cholinesterase Inhibitors, Including Pesticides and Chemical Warfare Nerve Agents U.S. Department of Health and Human Services
- MeSH Acetylcholinesterase+inhibitors
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