World Library  
Flag as Inappropriate
Email this Article

Competitive antagonist

Article Id: WHEBN0000654184
Reproduction Date:

Title: Competitive antagonist  
Author: World Heritage Encyclopedia
Language: English
Subject: Pharmacology, Receptor antagonist, Pharmacodynamics, Mifepristone, Alpha-Bungarotoxin
Collection: Pharmacodynamics, Pharmacology
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Competitive antagonist

A competitive antagonist is a receptor antagonist that binds to a receptor but does not activate the receptor. The antagonist will compete with available agonist for receptor binding sites on the same receptor. Sufficient antagonist will displace the agonist from the binding sites, resulting in a lower frequency of receptor activation.

Presence of a competitive antagonist will shift an agonism dose-response curve to the right.[1] A Schild plot for a competitive antagonist will have a slope equal to 1, and the X-intercept and Y-intercept will each equal the dissociation constant of the antagonist.[1]

Competitive antagonists are used to prevent the activity of drugs, and to reverse the effects of drugs that have already been consumed. Naloxone (also known as Narcan) is used to reverse opioid overdose caused by drugs such as heroin or morphine. Similarly, Ro15-4513 is an antidote to alcohol and flumazenil is an antidote to benzodiazepines.

A competitive antagonist can be reversible competitive antagonist or irreversible competitive antagonist.

References

  1. ^ a b Doseresponse curves in the presence of antagonists
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.