Parasympathetic Nervous System by Prof. Krouse Flashcards
What does hemicholinium inhibit?
Inhibit choline uptake at Na+/Choline Symporter
How does botox work?
What is it used to treat?
Prevents ACh vesicle fusion
Facial muscle spasms, strabismus (abnormal alignment of the eyes), wrinkles
Why is ACh used clinically?
Minor oculasr procedures for brief miosis (circulating AChE eats it up)
Why is Bethanochol used?
What is its mechanism of action?
Why don’t you give it IV?
Atonic gut, urinary retention after surgical procedures
M agonist
Powerful! Cardiac Arrest!
Why is Methacholine used? (Two reasons.)
To test for bronchoreactivity in case of asthma; reactivity
Diagnostic for bella donna poisoning
What is carbachol used for?
What is its mechanism of action?
Glaucoma if pilocarpine is ineffective
Muscarinic agonist with some nicotinic activity
What happens in mushroom poisoning?
Muscarine OD!
Why is Pilocarpine used?
What is its mechanism of action?
How does it work?
Acute/Emergecy Glaucoma treatment
muscarinic agonist
Contracts ciliary muscle to relieve intraocular pressure
What are the symptoms of muscarinic toxicity?
Think DUMBBELS or SLUDE
Diarrhea Urination Miosis Bronchorrea (increased mucus) Bradycardia Emesis Lacrimation Salivation Sweating
What are the symptoms of nicotinic toxicity?
Think MTWThF
Mydriasis Tachycardia Weakness (muscle paralysis) Th - hyperthermia Fasciculations
When would you see muscarinic and nicotinic toxicity simultaneously?
Organophosphate toxicity
Why is mydriasis and tachycardia present in nicotinic excess?
Overstimulation of nAChR at ganglia leads to depolarizing blockade
What is Edrophonium?
Why is used?
Reversible AChE inhibitor
diagnostic of myasthenia gravis
What is the difference between physostigmine and neostigmine? What are they both?
Physo - CNS action (tertiary amine); NEO - NO CNS action (quat amine with charge)
Both are reversible AChE inhibitors
Describe myasthenia gravis.
Autoimmune disorder with antibodies against nAChR receptors.
Why is neostigmine used?
treatment for MG; AChE inhibited 0.5-6 hrs
Ephedronium test
Normal - no change in grip strength
MG - increased grip strength
Why is pyridostigmine used? How does it work?
MG; reversible AChE inhibitor with longer lasting effects than neostigmine
What is DFP?
organophosphate used in glaucoma treatment
What is echothiophate?
Low lipid solubility irreversible AChE inhibitor
2nd line agent for glaucoma
Nerve gases
irreversible AChE inhibitors
What are Malathion and Parathion?
How do animals metabolize them?
How do humans metabolize them?
Insecticides which are prodrugs
S (inactive) via absorption O (active)
Back to O!
Which is more toxic: malathion or parathion?
Parathion
What’s the aging timelag for nerve gases vs. malathion?
sec/mins vs. 4-6 hrs.
How does 2-PAM work?
Regenerates AChE after organophosphate
Which AChE inhibitor would you use to treat atropine or TCA OD?
physostigmine (not neostigmine)
What is the treatment for AChE inhibitor toxicity?
Atropine+2-PAM+Mechanical Respiration
Why is physostigmine used?
Reverse atropine toxicity; Glaucoma treatment
Succinylcholine
NMJ paralysis, depolarizing block because it’s a long-acting agonist, short acting due to plasma AChE
Tubocararine
NMJ paralysis, competitive blocker, flaccid paralysis, short acting
Rocuronium/cisAtracurium
Fast onset, short-intermediate duration
How does atropine work?
What does it do?
What are some phrases to help remember its effects?
Competitive mAChR antagonist
mydriasis, cyclopegia, decreased GI activity, decreased secretions, relaxed lungs
Mad as a hatter (delirium), red as a beet (erythematous, blind as a bat (cyclopegia), dry as a bone (decreased secretions), hot as hell (thermoregulation)
What’s the clinical use of atropine?
Reverse the toxic effects of physostigmine or neostigmine (reversible AChE inhibitors)
Ipratropium is used to treat
Mechanism of action?
Asthma, COPD
Comptetivie muscarinic receptor antagonist
Tiotropium is used to treat?
Mechanism of acpiloction?
Ashtma, COPD
competitive muscarinic receptor antagonist
Benztropine is used to treat?
Mechanism of action?
drug-induced Parkinsonian symptoms
competitive muscarinic receptor antagonist
Scopolamine is used to treat?
Mechanism of action?
Motion sickness, diarrhea, decreased secretions
competitive muscarinic receptor antagonist
Propantheline is used to treat
Mechanism of action?
GI disorders (e.g. mild diarrhea)
competitive muscarinic receptor antagonist
A patients presents with iritis. What do you have her?
atropine
What receptors are in the ciliary body? Which division of the ANS controls it?
muscarinic, parasympathetic
How do you treat open-angle glaucoma?
beta blockers
How do you treat closed-angle glaucoma?
pilocarpine or surgery (punch holes into iris)
How does you treat chronic glaucoma?
timolol or latanoprost
How do beta blockers work on glaucoma?
Inhibiting the secretion of aqueous humor
How do the prostaglandins work on glaucoma?
What are their side effects?
Increasing outflow for another route
darken pupil, red eyes (inflammation)
Acetazolamide
Glaucoma treatment via decreased secretion
Nicotine
Insecticide, cigarettes
nicotinic receptor agonist
Why are Trimethapan and Mecamyline used?
What is their mechanism of action?
decreased BP during surgery (trimethapan), last resort in chronic hypertension because of its side effects (mecamyline)
Competitive nicotinic receptor antagonist @ the ganglia
