Antagonist: Difference between revisions
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Pharmacological antagonists can be further characterised as: | Pharmacological antagonists can be further characterised as: | ||
*[[Competitive antagonists|Competitive]] which binds to the binding site of a receptor and can be overcome by increasing the concentration of an [[Agonist|agonist]] (competitor). Example: Atropine, Tropicamide, Hyoscine (all these bind to muscarinic receptors)<ref>Rang, H. and Dale, M. (2012). Rang and Dale's pharmacology. Edinburgh: Elsevier/Churchill Livingstone pg160</ref><br> | *[[Competitive antagonists|Competitive]] which binds to the binding site of a receptor - via the induced fit method - and can be overcome by increasing the concentration of an [[Agonist|agonist]] (competitor). Example: Atropine, Tropicamide, Hyoscine (all these bind to muscarinic receptors)<ref>Rang, H. and Dale, M. (2012). Rang and Dale's pharmacology. Edinburgh: Elsevier/Churchill Livingstone pg160</ref><br> | ||
*[[Irreversible competitive antagonist|Irreversible competitive]] which forms a [[Covalent bond|covalent bond]] with the receptor. | *[[Irreversible competitive antagonist|Irreversible competitive]] which forms a [[Covalent bond|covalent bond]] with the receptor. | ||
*[[Non-competitive antagonist|Non-competitive antagonists]] which blocks the [[Signal transduction|signal transduction]] event of the [[Receptor|receptor]]. | *[[Non-competitive antagonist|Non-competitive antagonists]] which blocks the [[Signal transduction|signal transduction]] event of the [[Receptor|receptor]]. | ||
Revision as of 13:39, 22 October 2015
A compound (usually synthetic) that inhibits the action of its natural counterpart by binding to a receptor or protein. There are three classes of antagonist, chemical, physiological and pharmacological.
Pharmacological antagonists can be further characterised as:
- Competitive which binds to the binding site of a receptor - via the induced fit method - and can be overcome by increasing the concentration of an agonist (competitor). Example: Atropine, Tropicamide, Hyoscine (all these bind to muscarinic receptors)[1]
- Irreversible competitive which forms a covalent bond with the receptor.
- Non-competitive antagonists which blocks the signal transduction event of the receptor.
A pharmacalogical example of an antagonist is Tamoxifen, a drug which acts on estrogen receptor.
See also agonist.
References
- ↑ Rang, H. and Dale, M. (2012). Rang and Dale's pharmacology. Edinburgh: Elsevier/Churchill Livingstone pg160