Receptor antagonist

A receptor antagonist is a biological repressor molecule. A receptor antagonist slows down the cell by stopping some of the cell reactions by clogging up the areas that make the cell work. They are sometimes called blockers, such as beta blockers. An antagonist is a ligand which blocks or dampens a biological effect. It acts against an agonist. They may block enzymes or passages through cell membranes.
They are part of the homeostatic system which regulates the body physiology. Some are made for pharmaceutical uses.