Autonomic Pharmacology 5 (Ocular) Flashcards
Which organ serves as an autonomic pharmacology laboratory? (i.e. easy to observe autonomic symptoms)
the eye
Which receptor is found on the pupillary dilator? What does stimulation of this receptor cause?
alpha-adrenoreceptor –> mydriasis/pupil dilation
Which receptor is found on the circular, pupillary constrictor? What does stimulation of this receptor cause?
muscarinic receptor –> miosis/pupil constriction
What is another name for the pupillary dilator?
iris radial muscle
What is another name for the circular, pupillary constrictor?
iris sphincter
What receptor is found on the ciliary muscle? What does stimulation of this receptor cause?
muscarinic receptor; stimulation causes:
- contraction of the muscle
- myopia (for near vision)
- open trabecular meshwork –> aqueous humor outflow in canal of Schlemm to systemic circulation –> decrease IOP
What receptor is found on the ciliary epithelium? What does stimulation of this receptor cause?
beta-adrenoreceptor –> increased secretion of aqueous humor from CILIARY BODY
What are the 2 main classes of drugs used to treat glaucoma?
- M3 agonists
- beta-blockers
What is the difference between open angle glaucoma and angle closure glaucoma? Which one is more commonly treated with drugs?
open angle glaucoma: high pressure between cornea and iris (treated with drugs)
angle closure glaucoma: high pressure between ciliary body and iris
Name 6 drugs that can be used to treat glaucoma.
timolol
pilocarpine
physostigmine
adrenaline
apraclonidine
cannabinoids
What is timolol commonly used to treat? What class of drugs does it belong to? What is its mechanism for treatment?
treats: glaucoma
class: beta-blocker
mechanism: reduces secretion of aqueous humor from ciliary body –> decrease IOP
What is pilocarpine commonly used to treat? What class of drugs does it belong to? What is its mechanism for treatment? What are some off-target effects?
treat: glaucoma
class: muscarinic agonist
mechanism: ciliary muscle contraction –> aqueous humor outflow to canal of schlemm (to systemic circulation) –> decrease IOP
off-target effects: miosis, myopia
What is physostigmine commonly used to treat? What class of drugs does it belong to? What is its mechanism for treatment? What are some off-target effects?
treat: glaucoma
class: anticholinesterase
mechanism: ciliary muscle contraction –> aqueous humor outflow to canal of schlemm (to systemic circulation) –> decrease IOP
off-target effects: miosis, myopia
What are the 2 vasoconstrictor drugs used to treat glaucoma? What receptors do they mainly act on when used to treat glaucoma? Explain the mechanism of treatment?
drugs: adrenaline, apraclonidine
receptor: alpha adrenoreceptor
mechanism: vasoconstriction –> decrease blood clow to ciliary body –> decrease aqueous humor secretion –> decrease IOP
What is the mechanism behind cannabinoids being used to treat glaucoma?
relax trabecular network –> decrease IOP
Of all the drugs used to treat glaucoma, which one has no significant advantage over other drugs?
cannabinoids
What endogenous ligand are cannabinoids related to?
anandamide
What receptors do cannabinoids act on?
CB1 and CB2
What protein is the CB1 receptor coupled to? Explain its mechanism in relation to the trabecular network.
protein: Gi
mechanism: reduce transmitter release by decreasing Ca2+ influx and opening GIRK channels –> relax trabecular network
Which drug is used to dilate the pupil for ocular examination? What class of drugs does it belong to?
atropine (muscarinic antagonist)
TRUE or FALSE: the eyes are under both sympathetic tone and parasympathetic tone.
FALSE: the eyes are only under parasympathetic tone.
Which 2 drugs are used to test for horner’s syndrome?
cocaine and amphetamine
How does cocaine affect the pupil of normal people vs people with unilateral damage to sympathetic nerves or brainstem stroke?
normal with cocaine: pupil dilation
damage with cocaine: the pupil on the side with damage does not dilate
Which neuron in the oculo-sympathetic nerve pathway is amphetamine used to check? What will happen to the pupil if this neuron is damaged vs. intact?
neuron 3
damaged: no dilation of pupil
intact: dilation of pupil
