Cholinergic Drugs Flashcards
M1 receptor
G-protein linked, PLC pathway
M-1 was one half of the hip-hop duo Dead Prez
M2 receptor
Activates K+ channels, inhibits adenylyl cyclase
The M2 Browning is a heavy machine gun
M3 receptor
SM, secretory glands: similar to M1
vascular endothelium: NO
The M3 is a sporty car from BMW
Think of M-1 driving a BMW M3 on the M5 - all have similar mechanisms, except when the BMW M3 drives along blood vessels, in which case NO comes from the exhaust
M4 receptor
Similar to M2 receptor
The M4 Sherman was the U.S.’s main tank in WWII
Think of the U.S. in WWII with M4 Sherman tanks and M2 Browning machine guns (both have a similar mechanism)
M5 receptor
Similar to M1
The M5 is a highway in England
Think of M-1 driving a BMW M3 on the M5 - all have similar mechanisms
Acetylcholine
A choline ester muscarinic agonist (obviously)
Used in cataract surgery
“Heidi called to say she used ACh in her first cataract operation”
Carbachol
A choline ester muscarinic & nicotinic agonist
Uses: tx for glaucoma
“Barbara called (Carbachol) to say she smokes at the gym when she’s in agony (muscarinic & nicotinic agonist) and she needs meds for her glaucoma”
Bethanechol
A choline ester muscarinic agonist
Uses: tx of GI disorders and urinary bladder disorders
“Beth and Anne called (Bethanechol) to say their exercise program was agonizing (muscarinic agonist) and now Beth needs meds for a GI disorder and Anne needs meds for a urinary bladder disorder”
Pilocarpine
An alkaloid muscarinic agonist
Uses: tx of glaucoma
Other: causes profuse sweating
“I piloted my car into a pine (Pilocarpine) b/c I had tunnel vision from my glaucoma. I began to sweat when I saw that I would crash and afterwards my muscles were in agony (muscarinic agonist)”
Muscarine
An alkaloid muscarinic agonist (obviously)
Not used therapeutically but some mushrooms contain enough muscarine to produce intoxication
Think of MUShrooms CARryINg muscarin
Edrophonium
AChE inhibitor
Uses: dx/tx testing in myasthenia gravis, terminates the effects of NM blockers
Other: Contains a 4° ammonium so selective to NMJ
“He dropped the phone b/c he had myasthenia gravis”
“If you’re positive, then (N+) you don’t need to run any tests for myasthenia gravis”
Neostigmine
AChE inhibitor
Uses: tx of myasthenia gravis, ileus, SM atony, terminates the effects of NM blockers
Other: contains a 4° ammonium so selective to NMJ
“If you’ve been newly (Neo) diagnosed with myasthenia gravis, you may feel like there is a lot of stigma (Stigmine) associated with the disease”
It is a short-acting treatment for myasthenia gravis, so think of how many new (Neo) things don’t last long
Physostigmine
AChE inhibitor
Uses: tx of glaucoma
“His PHYSical appearance is SO terrifying b/c of his STIGmata, but he doesn’t notice how people are acting because of his glaucoma”
Pyridostigmine
AChE inhibitor
Uses: tx of myasthenia gravis
The pyramidal tracts contain axons originating in the motor cortex. Myasthenia gravis is a problem of the NMJ (motor end-plate).
Ambenonium
AChE inhibitor
Uses: tx of myasthenia gravis
“BEN will be far more AMbulatory once he takes Ambenonium for his myasthenia gravis”
Donepezil
AChE inhibitor
Uses: tx of Alzheimer’s disease
Other: easily crosses BBB
“Don’t write an epistle (Donepezil) until you’ve taken your Alzheimer’s meds or you’ll forget what to say”
Echothiophate
Organophosphate AChE inhibitor
Uses: tx of glaucoma
Other: Very polar, so not well absorbed
“I sat through a play called Echoes of Theo’s Fate, even though I couldn’t see much b/c of my glaucoma”
Malathion
Organophosphate AChE inhibitor
Used as a pesticide (rapidly broken down by birds and mammals but not fish and insects)
Other: Very lipid soluble, so rapidly absorbed
Think of the “mal” effects of pesticide overuse
Pralidoxime (2-PAM)
AChE reactivator that breaks the phosphate-AChE bond formed by organophosphates
Used to reverse the effects of organophosphate poisoning
Which drugs are carbamate esters?
“I’ll be stigmatized (-STIGMINE) if I can’t fix my own carburetor, Esther (Carbamate Ester)”
Which drugs are organophosphates?
“So man (Soman), the crowd’s laughter will have a DEAFening (DFP) echo (Echothiophate) if you run this marathon (Malation) in a sari (Sarin). It will have a nearly irreversible (organophosphates are nearly irrevesible AChE inhibitors) effect on your reputation as a serious runner.”
Atropine
Muscarinic antagonist
“His trophy wife - his bella donna - went for a jog and now her muscles are in agony”
Scopolamine
Muscarinic antagonist
Uses: CNS depressant
“Before we put a scope in old Armin’s head (Scopolamine), we’ll have to block his muscles and depress his CNS”
Cyclopentolate
Muscarinic antagonist
Uses: mydriasis
“I cycled to Penn too late (Cyclopentolate), even though my muscles felt like blocks and my eyes were wide because I was late”
Ipratropium
Muscarinic antagonist
Uses: bronchodilation
“I pray for a trophy (Ipratropium) - even though my muscles feel like blocks I have great lung capacity (bronchodilation)”
Pirenzepine
Selective M1 receptor antagonist
Uses: tx of peptic ulcer
“Peer in the zeppelin (pirenzepine) and you will see M-1 and all the guys from his block taking their peptic ulcer meds”
Tolterodine
Selective M2/M3 receptor antagonist
Uses: tx of urinary incontinence
“I may be told where to dine (Tolterodine) after the cops stopped my BMW M3 at a roadblock and took my M2 Browning, but at least I still have urinary continence”
Tubocurarine
Competitive Nm nicotinic antagonist
Uses: muscle block
Think of an indigenous South American with a curare-dipped dart and a blowgun tube (Tubocurarine). The curare dart causes muscle paralysis.
Succinylcholine
A depolarizing Nm nicotinic antagonist
Uses: muscle block
Interaction: can lead to malignant hyperthermia in susceptible individuals when mixed with volative anesthetics such as halothane
Think of how the ACh receptor still “sucks in” the (acetyl)choline (Succinylcholine) but nothing happens because the membrane is depolarized
Nicotine
Nn nicotinic agonist, causes “paradoxical” effects due to opposing actions and reflex reactions
Hexamethonium
Nn nicotinic antagonist
Since Nn receptors are found in both the sympathetic and parasympathetic nervous systems, hexamethonium will block the effects of whichever autonomic branch predominates at a particular site (peripheral vasculature and sweat glands have predominantly sympathetic tone, everything else has predominantly parasympathetic tone).
“The hex (witch) met only them (Hexamethonium) who could withstand a ganglionic block”
Trimethaphan
Nn nicotinic antagonist
Since Nn receptors are found in both the sympathetic and parasympathetic nervous systems, trimethaphan will block the effects of whichever autonomic branch predominates at a particular site (peripheral vasculature and sweat glands have predominantly sympathetic tone, everything else has predominantly parasympathetic tone).
“Have you tried to m(e)et a fan (Trimethaphan) of the gangly shot blocker Manute Bol?”
