AGONIST       • Agonist is a chemical(drug) that binds to the receptor and activates the receptor to produce biological response.                                             OR       • Agonist is a drug that produce effects on endogenous compounds, when it interacts with it’s receptor.     => Agonists are of following types:      (1) Full agonists     (2) Partial agonists     (3) Inverse agonists (1) Full Agonists       • If a drug binds to a receptor and produce maximal biological response that mimics the response to endogenous ligand is called full agonist.   - All full agonists for a receptor population should produce the same E max. For Example : phenylephrine is a full agonist at alpha1-adrenoceptors, because it produce the same E max as the endogenous ligand, norep...