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108 Cards in this Set

  • Front
  • Back
What kind of drug is Pilocarpine?
ACh agonist (muscarinic)
What kind of drug is Methacholine?
ACh agonist (muscarinic)
What kind of drug is Bethanecol?
ACh agonist (muscarinic)
What kind of drug is Carbachol?
ACh agonist (muscarininc and nicotinic)
What kid of drug is ACh?
ACh agonist (muscarinic and nicotinic)
What kind of drug is Nicotine?
ACh agonist (all nicotinic receptors)
What kind of drug is Varenicline?
ACh agonist (partial; selective for diff subtypes w/in the CNS)
What is the mechanism of action for Black Widow Spider Venom?
Promotes ACh release presynaptically so there is a constant release of ACh
What kind of drug is Phyostigmine?
AChE inhibitor (reversible)
What kind of drug is Rivastigmine?
AChE inhibitor (reversible)
What kind of drug is Neostigmine?
AChE inhibitor (reversible)
What kind of drug is Pyridostigmine?
AChE inhibitor (reversible)
What kind of drug is Erdophonium?
AChE inhibitor (reversible)
What kind of drug is Tacrine?
AChE inhibitor (rev)
What kind of drug is Donepizil?
AChE inhib (rev)
What kind of drug is Galantamine?
AChE inhib (rev)
What kind of drug is Echothiophate?
AChE inhib (irrev)
What kind of drug is Sarin nerve gas?
AChE inhib (irrev)
What kind of drugs are Malathion and Parathion?
AChE inhibs (irrev; insecticides)
What kind of drugs are "indirectly acting cholinomimetics"?
These are AChE inhibitors. Cholinomimetics because they affect a cholinergic response. Indirect because they don't do so by acting at the AChR like an agonist, but instead increase ACh in the synaptic cleft by inhibiting AChE.
What kind of drug is Atropine?
Competitive AChR antagonist
(muscarinic)
What kind of drug is Scopolamine?
Competitive AChR antagonist
(muscarinic)
What kind of drug is is Tolterodine?
Competitive AChR antagonist
(muscarinic)
What kind of drug is Oxybutynin?
Competitive AChR antagonist
(muscarinic)
What kind of drug is Tropicamide?
Competitive AChR antagonist
(muscarinic)
What kind of drug is Benztropine?
Competitive AChR antagonist
(muscarinic)
What kind of drug is Ipratropium?
Competitive AChR antagonist
(muscarinic)
What kind of drug is Tiotropium?
Competitive AChR antagonist (muscarinic)
What kind of drug is Propantheline?
Competitive AChR antagonist (muscarinic)
What kind of drug is d-tubocurarine?
Competitive AChR antagonist (nicotinic)
What kind of drug is Atracurium?
Competitive AChR antagonist (nicotinic)
What kind of drug is Pancuronium?
Competitive AChR antagonist (nicotinic)
What kind of drug is Vecuronium?
Competitive AChR antagonist (nicotinic)
What kind of drug is Rocuronium?
Competitive AChR antagonist (nicotinic)
What kind of drug is mecamylamine?
Competitive AChR antagonit (nicotinic)
What is the MOA for hemicholinium-3?
Inhibits uptake of choline into presynaptic terminals (Na+ dependent Choline transporter; CHT), thereby inhibiting ACh synthesis
What kind of drugs are:

Streptomycin, kanamucin, neomycin, gentamicin, etc.

And what is their effect on ACh release?
They are aminoglycoside antibiotics, and they prevent ACh release by blocking Ca2+ influx into the presynaptic terminal, inhbiiting fusion of the vesicle and the presynaptic membrane
What is the effect of high serum Mg2+ on release of ACh?
High serum Mg2+ inhibits ACh release from the presynaptic terminal by blocking Ca2+ influx and subsequent fusion of the vesicle with the presynaptic membrane
What is the MOA for Succinylcholine?
Succinylcholine causes the motor endplate to depolarize, halting transmission of ACh signalling to the muscle sarcolemma resulting in muscle paralysis. (Called a "Depolarizing Blockade")
A patient comes into your ER and is non-responsive, BP is in the tank, is sweating, and drooling. Friend says he had eaten a mushroom on a dare earlier in the day. What kind of poisoning is this patient suffering from and how would you treat it?
Patient is suffering from muscarine poisoning and you would treat with atropine or scopolamine (competitive AChR antagonists; both tertiary amines with good CNS penetration)
T or F: When acting on the ascending reticular core, atropine has 100x the sedating effect of scopolamine.
F: scopolamine has 100x the sedating effect of atropine
Scopolamine is used to treat sea-sickness. Where in the brain does it act, and how do we know this.
First, just for review, Scopolamine is a reversible mAChR antagonist.

Second, it acts somewhere between the semi-circular canals and the emetic center in the medulla. We know this because it does not alleviate emesis caused by drugs that directly stimulate the chemotrigger receptor zone (CTZ; medullary emetic zone).
What kind of drug is benztropine and what is it's therapeutic use?
Benztropine is a competitive mAChR antagonist. It is used in adjunct with anti-parkinsonian drugs to alleviate symptoms of parkinson's disease (atropine used for this as well)
What kind of drug is Pilocarpine, and what is its primary therapeutic use?
It is a muscarinic ACh agonist. Used topically in the eye to induce miosis which opens the canal of Schlemm and other drainage routes for intraocular fluid in the anterior chamber of the eye. USED AS Tx FOR GLAUCOMA!
What structure, under parasympathetic control ?(Cranial Nerve III), in the eye is the therapeutic target for muscarinic agonists?

What about muscarinic antagonists?
Agonists = sphincter pupillae (responsible for pupil constriction)

Antagonists = cilliary muscles responsible for altering the shape of the lens in the eye
Muscarine: tertiary or quaternary amine?
Tertiary (good membrane penetration)
Atropine: tertiary or quaternary amine?
Tertiary (good membrane penetration)
Scopolamine: tertiary or quaternary amine?
Tertiary (good membrane penetration)
Benztropine: tertiary or quaternary amine?
Tertiary (good membrane penetration)
Pilocarpine: tertiary or quatrenary amine?
Tertiary
Carbamylcholine: tertiary or quarternary amine?
Quaternary (poor membrane abs; good for topical use)
What is the other name for Carbamylcholine?
Carbachol
At what subset(s) of ACh receptors does Carbamylcholine work?
Almost all of them (nicotinic and muscarinic)
What two drugs are used as miotic agents in eye surgery (ex: lens replacement)?
Carbachol and Acetylcholine (NOT Pilocarpine)
Why is acetylcholine a suboptimal drug to administer IV in a small dose?
Because pseudoesterases in the plasma will break it down quickly
Is Carbachol metabolized by cholinesterases?
NO!
Define: Cycloplegia
Paralysis of the ciliary muscle of the eye (responsible for accommodation reflex; induced by mAChR antagonists)
What is the effect of ACh agonists (like pilocarpine, ACh, and carbachol) on the lens of the eye?
They induce contraction of the ciliary muscle which causes the lens to focus closely and blurs distance vision.
What is the effect of ACh antagonists (atropine, scopolamine) on the lens of the eye?

For what purpose is this effect beneficial?

Why do we want to avoid using atropine and scopolamine for the above purpose in patients with glaucoma?
The induce cycloplegia (paralysis of the ciliary muscle of the eye) which puts the lens in a fixed resting position and makes focusing at close distance impossible.

This is used in setting up corrective lenses.

We don't want to give these drugs (atropine and scopolamine) to people with glaucoma (or people with shallow anterior eye chambers at risk for glaucoma) because these drugs also induce mydriasis. This blocks the canal of Schlemm (due to passive pressure of the iris) and allows intraocular fluid to build up and intraocular pressure to increase. We specifically don't want to give atropine or scopolamine for this purpose since they are long acting agents (can act for days). Instead we give a shorter acting (hours) mAChR antagonist like tropicamide to everyone.
What kind of drug is Tropicamide, and why might we give it instead of other drugs in its class (hint: eyes)?
Tropicamide is a mAChR antagonist, and we give it over other drugs in the class (like atropine and scopolamine) since it is very short acting and does not run the risk of exacerbating glaucoma.
What kind of ACh receptors are found in the heart?
M2 (which act via a Gi G-protein; beta/gamma subunit more responsible for inc in K+ efflux that results in hyperpolarization of myocytes and slowed contraction tho)
What are the three areas in the heart to which muscarinic action is directed?
SA node, atria, and AV node
What are the three effects of M2 stimulation on the heart?
Negative inotropy (dec force of contraction), chronotropy (dec HR), and dromotropy (dec rate of conduction at the AV node)
What is the effect of increased K+ permeability due to M2 stimulation of the atrial pacemaker cells?

Hint: think about this as it relates to the three effects of M2 stimulation in the heart.
Resting phase hyperpolarization, and decreased slope of depolarization in pacemaker cells (causes negative chronotropy since we have a greater degree of depolarization at a slower rate of depolarization to overcome before we fire an action potential; negative dromotropy for the same reasons).

Increased permeability to K+ reduces the force of contraction (neg inotropy) in atrial myocytes due to the fact that the action potential is shorter (inc K+ permeability = higher rate of repolarization) and thuse there is less Ca2+ released from the sarcoplasmic reticulum and less influx of Ca2+ for the slow response Ca2+ channel that only opens when the cardiac myocyte is depolarized (less Ca2+ release/influx = lower force of contraction).
What kind of ACh receptor is found in the vascular bed?
M3 (although innervation is limited!)
What kind of G-protein do M3 receptors found in the vascular bed act via?
Gq (IP3 and DAG second messenger system)
What is the effect of cholinergic stimulation of M3 receptors found in the vascular bed?
Increase in intracellular calcium (Gq stim => activates PLC => PLC cleaves PIP2 to IP3 and DAG => IP3 stimulates release of Ca2+ from intracellular stores). Increased Ca2+ stimulates Ca2+ dependent NO synthase in the endothelial cell. NO (aka EDRF) is produced from arginine and diffuses out of the cell to the smooth muscle lining the vessel causing it to relax and resulting in vasodilation/dec BP.
What is the MOA for Vesamicol?
Blocks the vesicle associated ACh transporter preventing ACh from being placed w/in vesicles in the presynaptic terminal.
What is the effect of a low dose of IV ACh on the vaculature, and how does this ultimately effect the heart?
Low dose IV ACh only effects the vasculature due to rapid metabolism by pseudocholinesterases in the plasma. The effect on the vasculature is to vasodilate (ACh acts at M3 on endothelial cells, causes inc in Ca2+ via Gq, causes inc in NO due to Ca2+-dependent NO synthase, NO diffuses to smooth muscle to cause relaxation and dilation of vessel) resulting in dec BP. Dec BP is detected by baroreceptors which respond by increasing SS tone of the heart resulting in a reflexive tachycardia (!!!!! so not the effect you want if you're trying to deliver ACh to the heart !!!!!)

Need higher doses to achieve cardiac depression.
What are the two effects of ACh antagonists on the heart (namely atropine)?
Pronounced tachycardia and increased AV node conduction (so positive chronotropy/dromotropy)
What do low doses of atropine produce a paradoxical bradycardia?
Because atropine blocks presynaptic mAChRs that are responsible for negative regulation of ACh release leading to an increase in ACh release.
Why does atropine produce cutaneous vasodilation at toxic levels and in children?
Atropine blocks thermal sweating, so cutaneous vasodilation is the only way to dissipate heat (dry as a bone => red as a beet). Children more susceptible to hyperthermic effect.
Does parasympathetic stimulation directly relax the sphincters of the GI tract?
NO! They do relax, but it is due to PS stimulation of the enteric nervous system, and enteric nervous system release of peptides onto the sphincters that cause them to dilate.

Isolated sphincters (noteably the cardiac sphincter at the base of the esophagus because IT MAKES SENSE FOR REST AND DIGEST) contract when exposed to cholinergic agonists.
What kind of ACh receptor is found in the GI tract?
M3 (Gq MOA; results in increased contractility and frequency of contraction)
What kind of drug is Bethanecol?
ACh agonist that works primarily at muscarinic receptors in the GI tract and bladder
Is Bethanecol a tertiary or quaternary amine?
Quaternary (poorly absorbed, but acts on GI tract so given PO or Sub-Q [not sure why Sub-Q])
Why do we prescribe Bethanecol to someone, and when is it contraindicated?
Used to treat GI/GU (bladder) stasis (situations: post-partum, after general anaesthesia)

Contraindicated: When there is an obstruction causing stasis as increased pressure in lumen of intestine/bladder may cause perforation.
What is the general effect of muscarinic antagonists on the GI tract, and what can we derive from this as a possible side-effect of drugs such as atropine and scopolamine?
It depresses GI activity and thus we can derive that CONSTIPATION might be a side effect.
What kind of drug is Propantheline?
mAChR antagonist
Is Propantheline a tertiary or quaternary amine?
Quaternary
What is Propantheline indicated for?
GI tract hypermotility (spasmolytic)

FYI: Quaternary amines posses ganglionic blocking action too which increases their effectiveness as spasmolytics (tertiary amines like atropine and scopolamine lack this)
What is the effect of mAChR stimulation in the bladder?
Increased detrusor muscle tone which increases intravesicle pressure to set off the micturition reflex.
What are the two most selective drugs for stimulation of bladder mAChRs?
Bethanecol (direct agonist) and Neostigmine (AChE inhibitor)
Why are atropine-like drugs sometimes contraindicated in people with urinary tract blockages (ex: elderly men w/ prostatic hyperplasia)?
Because atropine like drugs can have a slight effect on urinary retention (although not total; hypothesized that other chemicals [ATP, NO] released from sacral parasympathetics to increase detrusor tone at sites other than cholinoceptors), and this patient population is more sensitive to this effect than the population as a whole
What kind of drug is oxybutynin?
Oxybutynin is a mAChR antagonist
Oxybutynin: tertiary or quaternary amine?
tertiary
What is Qxybutynin indicated for?
Overactive bladder (ex: spasmodic bladder following radical prostatectomy)
Where is Oxybutynin metabolised?
In the liver (CYP3A4)
What kind of drug is Tolterodine?
mAChR atagonist
What is Tolterodine indicated for?
Urinary urgency
Tolteridine: tertiary or quaternary amine?
tertiary
Where is tolteridine metabolized?
Liver (CYP2D6)
What kind of drugs are solifenacin, trospium, and darifenacin?
mAChR antagonists indicated for urinary urgency

*trospium is a quaternary amine so poorer abs, but less side-effects

*darifenacin exhibits some selectivity for M3 receptors
Which would have more side effects: a tertiary amine or quaternary amine drug?
Tertiary amine since it is more apt to spread systemically!
What kind of ACh receptors are found in the bronchiolar smooth muscle?
M3 (Gq => inc in Ca2+ => CONTRACTION OF BRONCHIOLAR SMOOTH MUSCLE!)
What kind of drug is Methacholine?
ACh agonist (muscarinic)
Methacholine: tertiary or quaternary amine?
quaternary
What is Methacholine used for?
Used in patients with inapparent asthma to try to induce bronchiloar hyper-reactivity (ACh agonist on M3 => inc Ca2+ => contraction of bronchiolar smooth muscle)

*Caution: Use only where there is support for person going into resp. distress!
What kind of drug is ipratropium?
mAChR antagonist
Ipratropium: tertiary or quaternary amine?
quaternary
What is ipratropium indicated for?
Aerosol inhalation treatment of bronchospasm (inhibits M3 activity in lung)
What kind of drug is Tiotropium?
mAChR antagonist
Tiotropium: tertiary or quaternary amine?
quaternary
What is tiotropium indicated for (and what is its advantage over ipratropium)?
Tiotropium is indicated for treatement of bronchospasm in asthma. It has less atagonist activity at the pre-synaptic M2 receptor and thus does not block negative regulation of ACh release.
What is the effect of Pilocarpine when it is administered orally?
Increased salivary secretion and sweating (used to treat xerostomia in H/N cancer patients and Sjoergren's syndrome [autoimmune salivary dysfxn])
What kind of drug is Cevimeline?
ACh agonist used to treat xerostomia
Where is Cevimeline metabolized?
Liver (CYP2D6, CYP3A3/4)
What receptors does Cevimeline exhibit some selectivity for?
M1 and M3