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. 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.
A competitive antagonist can be reversible competitive antagonist or irreversible competitive antagonist.
Famous quotes containing the word competitive:
“How deep is our desire to do better than our mothers—to bring daughters into adulthood strong and fierce yet loving and gentle, adventurous and competitive but still nurturing and friendly, sweet yet sharp. We know as working women that we can’t quite have it all, but that hasn’t stopped us from wanting it all for them.”
—Anne Roiphe (20th century)