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Cholinergic pharmacology
board prep
22
Medical
Graduate
03/03/2008

Additional Medical Flashcards

 


 

Cards

Term

 

 

 

Cholinergic junction

Definition

Choline + Acetyl CoA = Ach (packaged into vesicles)

Membrane depolarization leads to opening of Ca2+ channels and binding of the Ach vesicles w/ the membrane

Once in the junction it can bind to receptors (muscarinic or nicotinic), be metabolized by AchE, or diffuse back and bind to autoreceptor M2 

Term

 

 

 

Botulinum toxin

Definition

Inhibits synaptobrevin and other proteins to prevent ACh release

Term

 

 

 

AChE

Definition

Target for inhibitory drugs (indirect acting cholinomimetic)

 

Reversible AChE's: edrophonium, physostigmine, neostigmine

Irreversible AChE's: echothiophate, malathion, parathion

Term

 

 

 

Muscarinic receptor activation (Eye)

Definition

 

Sphincter -- M3 -- contraction, miosis

Ciliary muscle -- M3 -- contraction, accomodation

Term

 

 

 

Muscarinic Receptor activation (heart)

Definition

SA node -- M2 -- decrease HR (neg. chronotropy)

AV node -- M2 -- decrease conduction velocity (neg. dromotropy)

Term

 

 

 

Muscarinic receptor activation (lungs)

Definition

Bronchioles -- M3 -- contraction, bronchospasm

Glands -- M3 -- secretion

Term

 

 

 

muscarinic receptor activation (GI)

Definition

Stomach -- M3 -- increased motility, cramps

Glands -- M1 -- Secretion

Intestine -- M3 -- contraction, diarrhea

Term

 

 

 

muscarinic receptor activation (bladder)

Definition
Bladder -- M3 -- Contraction (detrusor), relaxation (sphincter) leads to voiding/ urinary incontinence
Term

 

 

 

muscarinic receptor activation (sphincters)

Definition
sphincters -- M3 -- relaxation of all except the lower esophageal to prevent reflux
Term

 

 

 

muscarinic receptor activation (glands)

Definition

Sweat glands -- M3 -- really sympathetic pathway

Salivation, lacrimation -- M3 -- rest of glands parasympathetic

Term

 

 

 

muscarinic receptor activation (blood vessels)

Definition

Endothelium -- M3 -- dilation via NO relaxing factor (no innervation, no effects of indirect agonists)

 

Only pharmacologically stimulated M3 muscarinic agonists will cause this dilation

Term

 

 

 

Muscarinic agonists (cholinomimetics)

Definition

Bethanechol = used to Rx ileus, urinary retention (people complaining of decreased GI/GU activity)

 

Methacholine = Dx bronchial hyperreactivity

 

Pilocarpine = Rx glaucoma (topical), xerostomia (dry mouth esp. in Sjogren's pts)

Term

 

 

 

Muscarinic agonists (AChE's inhibitors)

Definition

Endrophonium = Dx myasthenia, (also to differentiate myasthenia from cholinergic crisis)

 

Physostigmine = tertiary amine, Rx glaucoma, antidote to atropine overdose

 

Neostigmine = quaternary amine, Rx ileus, urinary retention, myasthenia, reversal of NM blockers

 

Donepezil = CNS entry, Rx alzheimer's dz (b/c loss of ACh neurons in Meynert's nucleus

 

Organophosphates = irreversible, lipid soluble, Rx glaucoma (MC used as insecticides malathion, parathion and nerve gas sarin)

Term

 

 

 

Toxicity of AChE inhibitors

Definition

SLUDGE or DUMBBELSS

D = diarrhea

U = urination

M = miosis

B = bradycardia

B = bronchoconstriction

E = excitation (muscle/CNS)

L = lacrimation

S = salivation

 Management of the muscarinic effects = atropine

Regeneration of AChE = pralidoxime (wedges in b/n drug and enzyme)

S = sweating

Term

 

 

 

Muscarinic antagonists

Definition

Atropine = bella donna alkaloid, tertiary amine that enters CNS (antispasmodic, antisecretory, antidiarrheal, manage AChE inhibitor OD)

 

Effects = decreased secretions, mydriasis, hyperthermia, tachycardia, sedation, urinary retention, constipation, behavioral excitation/hallucinations

Term

 

 

 

Other drug classes that are antimuscarinic

Definition

Antihistamines

TCA's

Antipsychotics (chlorpromazine, thioridazine)

Quinidine

Amantadine

Meperidine

Term

 

 

 

M blocker (tropicamide)

Definition

Used for ophthalamology (topical)

Term

 

 

 

M blocker (Ipratropium)

Definition
Asthma and COPD (inhalational), no change in mucus viscosity
Term

 

 

 

M blocker (Scopolamine)

Definition
Motion sickness, causes sedation and short-term memory block
Term

 

 

 

M blocker (Benztropine, trihexyphenidyl)

Definition
Lipid soluble (CNS entry) used in parkinsonism and acute extrapyramidal sxs induced by antipsychotics
Term

 

 

 

M blocker (Tolterodine, Oxybutynin)

Definition
Used for urinary incontinence
Term

 

 

 

Nicotinic receptor angatonists (ganglion blocking agents)

Definition
 Mecamylamine = prevents baroreceptor reflex changes in HR (used in severe HTN)
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