Active and in active conformations exist in

active and in-active conformations exist in equilibrium
 Histamine  agonist  active > inactive
 Anti-histamine  inverse agonist  inactive > active
 Adrenergic Agonists
o β-adrenergic antagonists (β-blockers)
 MOA  block β
1
receptors on the ciliary body
 Decrease production of aqueous humor
 Ex: Timolol
o α
2
-adrenergic agonists
 MOA  activate presynaptic α
2
receptors  decrease NT release
 Decrease production of aqueous humor
 Ex: Brimonidine
 Cholinergic Agents
o MOA  direct agonists or AChE inhibitors
o Activate muscarinic receptors on iris and ciliary body  contraction (Miosis)  enlarging
angle  increased drainage
o Increase drainage of aqueous humor
o Ex: Pilocarpine—agonist
 Prostaglandins  analogs of F2α
o MOA  remodeling of extracellular matrix
o Increased drainage of aqueous humor
o Ex: Latanoprost
 Carbonic Anhydrase Inhibitors
o MOA  carbonic anhydrase catalyzes the formation of carbonic acid

o  bicarbonate is required for production of aqueous humor 
o ↓H
2
CO
3
leads to  ↓ HCO
3
- and  ↓ aqueous humor
o Example: Brinzolamide