Final answer:
Epinephrine is used in the treatment of glaucoma by reducing intraocular pressure through its action on alpha-1 adrenergic receptors, causing vasoconstriction of blood vessels and decreasing aqueous humor production.
Step-by-step explanation:
Epinephrine, an α₁ agonist, can be used in the treatment of glaucoma by reducing intraocular pressure. This occurs through the vasoconstriction of blood vessels due to its action on α₁ adrenergic receptors. The effect is similar to that of catecholamines, which constrict both afferent and efferent arterioles in the kidneys, but when it comes to the eye, epinephrine decreases the production of aqueous humor, which in turn reduces the pressure inside the eye. It's interesting to note that another medication, pilocarpine, which is a muscarinic agonist, can act to reduce intraocular pressure related to glaucoma by causing the drainage of aqueous humor.