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:
“Women of my age in America are at the mercy of two powerful and antagonistic traditions. The first is the ultradomestic fifties with its powerful cult of motherhood; the other is the strident feminism of the seventies with its attempt to clone the male competitive model.... Only in America are these ideologies pushed to extremes.”
—Sylvia Ann Hewitt (20th century)