Partial agonist

Partial Agonist

A partial agonist (pronunciation: /ˈpɑːrʃəl ˈæɡənɪst/) is a type of pharmacological agent that, while having the ability to bind and activate a given receptor, only has a partial efficacy at the receptor relative to a full agonist.

Etymology

The term "partial agonist" comes from the Latin pars, meaning "part", and the Greek ἀγωνιστής (agonistēs), meaning "combatant, champion".

Pharmacology

In Pharmacology, a partial agonist is a drug that binds to and activates a given receptor, but has only partial efficacy at the receptor relative to a full agonist. They may also be considered ligands which display both agonistic and antagonistic effects - when both a full agonist and partial agonist are present, the partial agonist actually acts as a competitive antagonist, competing with the full agonist for receptor occupancy and producing a net decrease in the receptor activation observed with the full agonist alone.

Related Terms

Agonist: A substance which initiates a physiological response when combined with a receptor.
Antagonist: A type of receptor ligand or drug that blocks or dampens a biological response by binding to and blocking a receptor rather than activating it like an agonist.
Receptor (biochemistry): A protein molecule that receives chemical signals from outside a cell.
Pharmacology: The branch of medicine concerned with the uses, effects, and modes of action of drugs.
Ligand (biochemistry): A substance that forms a complex with a biomolecule to serve a biological purpose.