L2 Flashcards
Remind yourself… what are the muscarinic receptors? Where are they?
CHOLINGERIC receptors - bind ACh!!! M1 - ganglia - slow EPSP M2 - Ganglia - IPSP - Heart = ↓HR & contractility M3 - on GI, eyes, BVs, etc - Smooth muscle contraction - Gland secretion
Are muscarinic receptors ion channels or GCPRs?
7TM GCPR
M1 & 3 - Gq
M2 - Gi
Which muscarinic receptors are found in the GI? Fxn of each.
M3 - mediates smooth muscle contraction = motility; secretions
M2 - inhibits relaxation
Working together to maintain basal parasympa tone
Which muscarinic receptors are found in BVs? Fxn of each?
Usually para sympa has no influence on BVs
But BVs do express M3 receptors that bind circulating ACh (not directly innervated by para) to aid relaxation
What is the fxn of muscarinic receptors at sphincters?
M3 (M1?) = relax sphincter
What are the 4 muscarinic agonists?
Carbamylcholine
Acetyl-beta-methylcholine
Bethanechol
Pilocarpine
Which muscarinic agonist works at the heart? What would the effects there be?
Acetyl-beta-methylcholine
Net parasympa tone
What muscarinic agonist works at the GI, bladder, and eye but is muscarinic only (vs nicotinic > muscarinic)?
Bethanechol
What muscarinic agonist works at the GI, bladder, eye, and is nicotinic > muscarinic?
Caramylcholine
Which muscarinic agonist is hydrophobic and used to treat the eye?
Pilocarpine
Which 2 muscarinic agonists are resistant to AChE hydrolysis?
Resistant = bethanechol & carbamylcholine
Slow AChE hydrolysis = ABM
What is the mneumonic for parasympa overstim = OD on muscarinic agonists?
SLUDE Salivation Lacrimation Uriniation Defication GI motility Emesis = vomiting
What are the cardiovas symptoms of para overstim?
Hypotension - M3 vasodilation
Bradycardia - M2 at SA node and myocardium
What are the resp symptoms of para overstim?
Bronchoconstriction
↑secretions
Both M3
What are the GI symptoms of para overstim?
Vomiting
Ab cramps - activated smooth muscle
What are the gland symptoms of para overstim?
↑Saliva, lacrimation, sweating
What are the ocular symptoms of para overstim?
Constricted pupil - M3 on sphincter muscle
Spasm of accomidation - M3 @ ciliary body
Explain the use of pilocarpine for glaucoma
Constricts circular muscles of eye - open iris - opens drainage canals
Why would you use a muscarinic agonist for cateract extraction?
Stretch iris for suturing room
What drug should you use for GI procedures? Why?
Bethanechol
Post-op obstruction, congenital megacolon, GERD
1. Create tone during surgery
2. Increase tone in sphincter to keep contents from refluxing
Which drug do you use for urinary retention?
Bethanechol
Which drug do you use for dry mouth?
Pilocarpnie applied directly to salivary gland
6 contraindications for using muscarinic agonists
Asthma Hyperthyroidism - AFib Coronary insufficiency Peptic ulcers Mechanical or inflam cause of GI obstruction/urinary tract Peritonitis
What are the 5 non-selective muscarinic ANTagnoists?
Atropine Scopolamine Tropicamide Cyclopentolate Glycopyrrolate
What are the 4 selective muscarinic antagonists? What are each’s affinity?
Pirenzepine - M1, medium M3
Tiotropium - M1 & M3, low M2
Tolterodine & darifenacin - M3
Why do you use tolterodine/darifenacin?
Detrusor muscle in bladder
Goal to constrict sphincter
Which muscarinic antagonist do you use for colds - why?
Ipratropium bromid
Relaxes bronchial smooth muscle
Why would you use anti-muscarinics for chronic rhinitis?
↑airway passage
↓secretions
Which muscarinic antagonists could you use for chronic bronchitis/emphysema? Why these specifically?
Increase airway passage with NO change to sputum viscosity
Which 2 drugs for intestinal hypermotility or diarrhea?
- Glycopyrrolate
2. Pirenzepine
Which 2 drugs do you use for overactive bladder?
Darifenacin
Tolterodine
Selective for M3 receptor in detrusor muscle
Which 2 drugs could you use to gain airway access for intubation pre-surg, prevent vagal reflexes during surg, and to recover from anesthesia?
Glycopyrrolate = charged Atropine = uncharged
Which muscarinic antagonists are used to examine the retina and optic disc?
Cyclopentolate
Tropicamide - shortest acting option!
Drug for motion sickness
Scopolamine prophylactically
Block M3 receptors
- Vestibular
- Vomiting center @ nucleus of solitary tract
3 contraindications for muscarinic antagonists
Narrow angle glaucoma
Cardiac arrhythmia
Chronic lung disease - most will be drying
- Exceptions = ipratropium & tiotropium
Symptoms of mushroom poisoning. treatment?
Mushrooms have muscarine - symptoms of OD: - Perspiration - Lacrimation - Salivation Treat with ATROPINE
