Parasympathomimetic drug
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A '''parasympathomimetic drug''' is a [[medication|drug]] or [[poison]] that acts by stimulating or '''''mimicking''''' the [[parasympathetic nervous system]] (PSNS).<ref name="urlDorlands Medical Dictionary:parasympathomimetic">{{cite web |url=http://www.mercksource.com/pp/us/cns/cns_hl_dorlands_split.jsp?pg=/ppdocs/us/common/dorlands/dorland/six/000078652.htm |title=Dorlands Medical Dictionary:parasympathomimetic |format= |work= |accessdate=}}</ref> These chemicals are also called [[cholinergic]]s because [[acetylcholine]] (ACh) is the [[neurotransmitter]] used by the PSNS. Chemicals in this family can act either directly by stimulating the [[nicotinic acetylcholine receptor|nicotinic]] or [[muscarinic acetylcholine receptor|muscarinic]] receptors, or indirectly by inhibiting [[cholinesterase]], promoting acetylcholine release, or other mechanisms. <ref>Brenner, G. M. (2000). ''Pharmacology.'' Philadelphia, PA: W.B. Saunders Company. ISBN 0-7216-7757-6</ref>
Some [[chemical weapons]] such as [[sarin]] or [[VX (nerve agent)|VX]], non-lethal [[riot control agent]]s such as [[CS gas|tear gas]], and insecticides such as [[diazinon]] fall into this category.
==Pharmaceuticals==
===Direct-acting===
These act by stimulating the [[nicotinic acetylcholine receptor|nicotinic]] or [[muscarinic acetylcholine receptor|muscarinic]] receptors.
*'''Choline esters'''
**[[Acetylcholine]] (all [[acetylcholine receptors]])
**[[Bethanechol]] ([[M3 receptors]])
**[[Carbachol]] (all [[muscarinic receptors]] and some [[nicotinic receptors]])
**[[Methacholine]] (all [[muscarinic receptors]])
*'''Plant alkaloids'''
**[[Nicotine]]
**[[Muscarine]]
**[[Pilocarpine]] ([[M3 receptors]])
===Indirect-acting===
Indirect acting parasympathomimetic drugs may be either reversible cholinesterase inhibitors, irreversible cholinesterase inhibitors or drugs that promote ACh release or [[anti-adrenergic]]s. The latter inhibits the antagonistic system, the [[sympathetic nervous system]].
*'''Reversible cholinesterase inhibitors'''
**[[Donepezil]]
**[[Edrophonium]]
**[[Neostigmine]]
**[[Physostigmine]]
**[[Pyridostigmine]]
**[[Rivastigmine]]
**[[Tacrine]]
*'''Irreversible cholinesterase inhibitors'''
**[[Echothiophate]]
**[[Isoflurophate]]
**[[Malathion]]
*'''ACh release promoters'''
**[[Cisapride]]
**[[Metoclopramide]]
*'''[[Anti-adrenergic]]s'''
**[[clonidine]] (α-[[adrenergic agonist|receptor agonist]], [[Alpha-2 receptor|α<sub>2</sub>]] > [[alpha-1 receptor|α<sub>1</sub>]], giving [[negative feedback]])
**[[propranolol]] ([[non-selective Beta adrenergic receptor|β2]] antagonist)
**[[atenolol]] ([[Beta-1 adrenergic receptor|β1]] antagonist)
**[[prazosin]] ([[alpha-1 receptor|α1]] antagonist)
**[[methyldopa]] ([[Alpha-2 receptor|α<sub>2</sub>]] agonist giving [[negative feedback]])
==References==
<references/>
==See also==
* [[Sympathomimetic drug]]
==External links==
* {{MeshName|Parasympathomimetics}}
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{{Receptor agonists and antagonists}}
{{Parasympathomimetics}}
{{Antiglaucoma preparations and miotics}}
[[Category:Parasympathomimetics]]
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