Navigation Menu Search PhysiologyWeb
PhysiologyWeb Logo
PhysiologyWeb
  Home  |  FAQ  |  About  |  Contact  |   - Sign In
 Search PhysiologyWeb
   
Home > Glossary > A > Antagonist

Glossary of Physiology Terms -
Antagonist

— share —
Share on Facebook    Share on X    Share on LinkedIn    Share on Pinterest    Share on Reddit    Email    Copy URL

Antagonist

Definition:
An antagonist is a molecule that binds to a receptor, however, it does not activate the physiological response induced by the naturally occurring physiological ligand of the receptor. Moreover, once bound to the receptor, an antagonist prevents the physiological ligand from activating the receptor. Therefore, antagonist binding to a receptor prevents or blocks the action of the natural ligand.

For example, acetylcholine (ACh) is the naturally occurring physiological ligand that activates nicotinic and muscarinic acetylcholine receptors. Tubocurarine and succinylcholine are antagonists of the nicotinic ACh receptor (nAChR), and atropine is an antagonist of the muscarinic ACh receptor (mAChR).

Related glossary terms/phrases:
Agonist




Posted: Tuesday, January 14, 2014
Last updated: Wednesday, March 12, 2025
— share —
Share on Facebook    Share on X    Share on LinkedIn    Share on Pinterest    Share on Reddit    Email    Copy URL