Definitions of Common Pharmacologic Terms
| Term | Definition |
| Agonist | A molecule that binds to a receptor and elicits a response by the cell |
| Antagonist | A molecule that binds to a receptor, but rather than causing a response, blocks the binding of an agonist, so preventing the response |
| Affinity | The tightness with which an agonist/antagonist binds to a receptor (described using the dissociation constant) |
| Selectivity | Activity of an agonist against a limited number of receptors |