Autonomic Innervation of the Eye Flashcards
Pilocarpine
Muscarinic Agonist (for testing parasympathetic innervation) Treats Glaucoma
Atropine
Muscarinic Antagonist (dilates pupil via inhibition of parasympathetic nerves)
Cocaine
Blocks axoplasmic pump to increase NE concentrations
Should produce mydryasis (indicating intact sympathetic innervation)
Amphetamine
Releases NE in basal concentrations (not in vesicles)
Should produce mydryasis if the postganglionic sympathetic nerve is intact
Horner’s Syndrome
No response to cocaine indicating Sympathetic Nerve Damage
Phenylephrine
Dilates pupil through alpha1 adrenergic (NE) stimulation
Epinephrine
Treats glaucoma by increasing aqueous humor outflow and inhibiting formation
Parasympathetic Nervous System Actions
Focuses eye for near vision (ciliary muscle contraction)
Constricts pupil (Miosis - pupillary sphincter contraction)
Enhances aqueous humor drainage (Canal of Schlemm)
–All through AcH acting on muscarinic receptors
Sympathetic Nervous System Actions
Alpha 1 Adrenergic (NE) Receptors:
Mydriasis through contraction of pupillary dilator muscle
Holds eyelid open through contraction of superior tarsal muscle
Beta 2 (Epinephrine) Receptors
Relaxes ciliary muscle for distant vision
Increases aqueous humor formation
Alpha 2 receptors
Inhibits aqueous humor formation
Physostigmine, Ecothiophate
Treatment of Narrow Angle Glaucoma through preventing acetylcholine degradation
Terazosin
Alpha 1 Receptor Antagonist
Reserpine
Noepinephrine depleting agents
Timolol
Decrease aqueous humor formation by Blocking Beta receptors
Treats Glaucoma
Physostigmine and Ecothiophate
Anticholinesterases that enhance aqueous humor drainage through canal of Schlemm
Treats Glaucoma
Alpha 2 Agonists such as Apraclonidine and Brimonidine
Reduces aqueous humor formation
Treats Glaucoma
