Cholinergic Agonists And Antagonists 2

Question 1

Actuation of which receptor most likely evoke the greatest vasodilation by acting on receptors of the vascular smooth muscle?

Answer 1

β2

Activation of α1 receptors causes vasoconstriction

Question 2

What the 3 different classes of cholinergic antagonists?

Answer 2

• muscarinic receptor antagonists
• nicotinic receptor antagonists: ganglion blockers and NMJ blockers
• drugs that act presynaptically

Question 3

Atropine is a ________

Answer 3

Reversible competitive Muscarinic receptor antagonist and thus prevents acetylcholine from binding at that site

Question 4

_______, ________,. And _______ drugs have significant anti muscarinic effects

Answer 4

Antihistaminic, antipsychotic, and antidepressant

Question 5

Atropine is a ______ amine

Answer 5

Tertiary; CNS and peripheral muscarinic blocker

Question 6

Effects of atropine on the eye, GI and urinary system

Answer 6

Eye: mydriasis (dilation), cyclopegia (relax of lens to see farther)
GI: ↓ gastric motility
Urinary system: ↓ hypermotility of urinary bladder

Question 7

What is the effect of LOW dose atropine on the heart?

Answer 7

BRADYCARDIA due to: blockage of the presynaptic M2 receptors which normally inhibit acetyl choline release

Question 8

What is the effect of moderate to high therapeutic doses of atropine on the heart?

Answer 8

TACHYCARDIA due to: blockade of the atrial M2 receptors which are post synaptic and causes opposite effects of muscarinic receptors

Question 9

Atropine flushing is cutaneous vasodilation seen with ________

Answer 9

High doses of atropine

Question 10

Effect of atropine on glands:

Answer 10

Salivary, sweat and lachrymal glands are BLOCKED

Blockage of sweat glands can cause high body temperature (fever)

Question 11

Adverse effects of atropine

Answer 11

• dry mouth, blurred vision, sandy eyes, tachycardia, constipation, urinary retention
• effects on CNS: restlessness, confusion, hallucinations, delirium’s which can progress to depression, and collapse of circulatory and respiratory systems and death

Question 12

What is the use of scopolamine?

Answer 12

Prevention of motion sickness

Sometimes used in anesthesia procedures because it blocks short term memory

Question 13

What are the two classes of synthetic and semisynthetic drugs:

Answer 13

Quaternary ammonium muscarinic antagonists

Tertiary amine muscarinic antagonists

Question 14

What are the two quarternary ammonium muscarinic antagonists and what is their main use

Answer 14

• ipratropium and tiotropium
• used as inhalation drugs in the treatment of COPD and sometimes asthma
  They block M3 receptors → bronchodilation

Question 15

_________ is used in inhalational drugs for treating COPD

Answer 15

Ipratropium or tiotropium

Question 16

What are the tertiary amine muscarinic antagonists?

Answer 16

Homatropine and tropicamide

Question 17

___________ is preferred over atropine for mydriasis for funcodscopy because it has a shorter duration fo action

Answer 17

Homatropine or Tropicamide

Question 18

Which tertiary amine muscarinic antagonists are used to treat Parkinson’s and the extrapyramidal effects of antipsychotic drugs?

Answer 18

Benztropine and trihexyphenidyl

Question 19

Uses of glycopyrrolate

Answer 19

• orally to inhibit GI motility

- paraenterally to prevent bradycardia during surgery

Question 20

_________ is used for an overactive bladder

Answer 20

Tolterodine

Question 21

Antimuscarinic agents are contraindicated in:

Answer 21

• patients with angle closure glaucoma
• careful with patients with prostatic hypertrophy
• elderly patients

Question 22

What are the two mechanism of ganglion blocker drugs in the anti nicotinic agents

Answer 22

• prolonged depolarization: nicotine

- antagonism of nicotinic receptors: hexamethonium and mecamylamine

Question 23

_________ and ________ are antinicotinic receptor drugs that cause ganglion blockade by directly antagonizing the nicotinic receptors

Answer 23

Hexamethonium and mecamylamine

Question 24

The effect of ganglion blockers is to ____________

Answer 24

Remove dominant control of various organs

Question 25

What are the two types of neuromuscular blockers?

Answer 25

• competitive antagonists (non depolarizing blockers): tubocurarine
• agonists (depolarizing blockers): succinylcholine

Question 26

What are some adverse effects of depolarizing agents?

Answer 26

• malignant hyperthermia due to excessive release of calcium from SR

Question 27

_____________ is given to treat the adverse effect of malignant hyperthermia seen when giving depolarizing agents

Answer 27

Dantrolene

Question 28

Malignant hyperthermia is an adverse effect seen when giving ____________

Answer 28

Succinylcholine and halogenated anesthetic

Question 29

What drug is an inhibitor of acetylcholine synthesis? What is is its mechanism of action?

Answer 29

Hemicholinium-3

Blocks choline transporter 1 aka CHT1 (symport with sodium) and prevents the uptake of choline required to synthesize acetylcholine

Question 30

What is the mechanism of action of vesamicol?

Answer 30

It is a acetylcholine storage inhibitor

Blaise the Acetylcholine-H antiporter that is used to transport acetylcholine into vesicles

Question 31

Mechanism of action of botulinum toxin

Answer 31

Inhibits acetylcholine release

Question 32

An ophthalmologist gives a patient a drug to dilate her pupils. What kind of drug did she give the patient?

Answer 32

M3 antagonist