Nicotinic antagonist
Drug that inhibits the action of acetylcholine at nicotinic acetylcholine receptors
A nicotinic antagonist is a type of anticholinergic drug that inhibits the action of acetylcholine (ACh) at nicotinic acetylcholine receptors. These compounds are mainly used for peripheral muscle paralysis in surgery, the classical agent of this type being tubocurarine,[1] but some centrally acting compounds such as bupropion, mecamylamine, and 18-methoxycoronaridine block nicotinic acetylcholine receptors in the brain and have been proposed for treating nicotine addiction.[medical citation needed]
| Mechanism | Antagonist | Preferred receptor | Clinical use |
|---|---|---|---|
| Ganglionic blocking agents | Hexamethonium | Ganglion type | None[2] |
| Mecamylamine | Ganglion type | ||
| Trimethaphan | Ganglion type | Rarely used for blood pressure decrease during surgery[2] | |
| Nondepolarizing neuromuscular blocking agents | Atracurium | Muscle type | Muscle relaxant in anaesthesia[2] |
| Doxacurium | Muscle type | ||
| Mivacurium | Muscle type | ||
| Pancuronium | Muscle type | Muscle relaxant in anaesthesia[2] | |
| Tubocurarine | Muscle type | Discovered in arrow poison it was the first pheripheral muscle relaxant. Rarely used since 1980s.[2] | |
| Vecuronium | Muscle type | Muscle relaxant in anaesthesia[2] | |
| Depolarizing neuromuscular blocking agents | Succinylcholine* | Muscle type | |
| Centrally acting nicotinic antagonists | 18-Methoxycoronaridine | α3β4 | |
| Bupropion | α3β4. α4β2, α1β1γδ | Antidepressant (NDRI) | |
| Hydroxybupropion | α3β4. α4β2, α1β1γδ | Antidepressant (NDRI). Metabolite of bupropion. | |
| Threohydrobupropion | α3β4. | Antidepressant (NDRI). Metabolite of bupropion. | |
| Dextromethorphan | α3β4. α4β2, α7 | Common over the counter antitussive. | |
| Dextrorphan | α3β4. α4β2, α7 | Metabolite of dextromethorphan; no accepted medical uses. | |
| 3-Methoxymorphinan | α3β4 | Secondary metabolite of dextromethorphan; not used in medical practice. Unknown medical efficacy. |
- Note: Succinylcholine is a nicotinic agonist. See neuromuscular blocking agents page for details on the mechanism of action.
See also
- Nicotinic acetylcholine receptor
- Nicotinic agonist
- Muscarinic acetylcholine receptor
- Muscarinic agonist
- Muscarinic antagonist
References
- ^ P. Taylor (1990). In Goodman and Gilman's The Pharmacological Basis of Therapeutics, 8th Ed., (A. G. Gilman et al., Eds.), pp. 166-186, New York: Pergamon Press.
- ^ a b c d e f Rang, H. P. (2003). Pharmacology. Edinburgh: Churchill Livingstone. ISBN 0-443-07145-4. Page 149
External links
Media related to Nicotinic antagonists at Wikimedia Commons- Nicotinic+antagonists at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
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- ♦ Receptor: Agonist
- Partial agonist
- Antagonist
- Inverse agonist
- Positive allosteric modulator (PAM)
- Negative allosteric modulator (NAM)
- ♦ Miscellaneous: Precursor
- Cofactor
| Enzyme | see Enzyme inhibition |
|---|---|
| Ion channel | See Ion channel modulators |
| Receptor & transporter | |
| Miscellaneous |
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