Autonomic Drugs - Cholinergics (Krasowski)

Question 1

direct transmission from the central nervous system, as well as post-ganglionic parasympathetic neurons, use what neurotransmitter?

Answer 1

acetylcholine

Question 2

post-gangionic sympathetic neurons use this neurotransmitter, with what exception?

Answer 2

norepinephrine (except for certain sweat glands, which use acetylcholine)

Question 3

neurotransmitter that acts at receptors in the renal vasculature, influencing blood flow

Answer 3

dopamine

Question 4

neurotransmitter that is produced in the adrenal medulla, transported in the blood, and can activate most adrenergic receptors.

Answer 4

norepinephrine

Question 5

what enzyme is found in the adrenal medulla that is required for the conversion of norepinephrine to epinephrine?

Answer 5

phenethanolamine N-methyltransferase

Question 6

what is the rate limiting step in the catecholamine synthesis pathway?

Answer 6

conversion of L-tyrosine to L-dopa by tyrosine hydroxylase

Question 7

Which of the following is an INCORRECT statement regarding muscarininc acetylcholine receptors?

A. The prototype agonist muscarine comes from mushrooms
B. The endogenous agonist is acteylcholine
C. They are found on targets of sympathetic innervation
D. Their release of acetylcholine is impaired by the toxin botulinum
E. When activated they tend to increase secretions and intestinal activity

Answer 7

C.

They are found on targets of parasympathetic innervation.

Question 8

Which of these muscarinic receptor subtypes is INCORRECTLY matched with its site of action?

A. M1 - GI tract
B. M2 - cardiac
C. M3 - glandular/smooth muscle
D. M4 - central nervous system
E. M5 - unclear function

Answer 8

A.

M1 receptors are found on postganglionic neurons (ie, the ‘neural’ receptor subtype)

Question 9

Which of the muscarinic receptors act via the inositol triphosphate (IP3) pathway involved in smooth muscle contraction?

Answer 9

odd-numbered (M1, M3, M5)

Question 10

Which of the muscarinic receptors act by inhibiting adenyly cyclase? What is the effect of this?

Answer 10

even-numbered (M2, M4); this reduces cAMP in the cell, creating an inhibitory effect

Question 11

class of receptors present at neuromuscular junctions, autonomic pre-ganglionic terminals, and the brain

Answer 11

nicotinic acetylcholine receptors

Question 12

this receptor agonist is involved in complex pathways affecting cognitive function and reward

Answer 12

nicotine

Question 13

partial agonist of α4β2 neuronal nicotinic receptors that helps treat nicotine dependence

Answer 13

varenicline

Question 14

what is the therapeutic use for the nicotinic receptor antagonists mivacurium, pancuronium, and vecuronium?

Answer 14

used as neuromuscular blockers, primarily in surgeries to prevent smooth muscle contraction

Question 15

inhibitors that affect both muscarinic and nictonic receptors and include neuromuscular reversal agents and myasthenia gravis drugs

Answer 15

acetylcholinesterase inhibitors

Question 16

pesticides, insecticides and nerve gas are examples of _____ AChE inhibitors

Answer 16

organophosphate

Question 17

AChE inhibitor that is used to reverse neuromuscular blockers (e.g., vecuronium, pancuronium)

Answer 17

neostigmine

Question 18

AChE inhibitor that is used most often in the treatment of myasthenia gravis

Answer 18

pyridostigmine

Question 19

this conidition is the antibody-mediated destruction of muscle nicotinic acetylcholine receptors leading to skeletal muscle fatigue

Answer 19

myasthenia gravis

Question 20

donepezil, galantamine, and rivastigmine are examples of this class of drug, used in the palliative treatment of Alzheimer’s disease

Answer 20

AChE inhibitors

Question 21

what does the term ‘aging’ mean, as applied to a unique property of organophosphate AChE inhibitors like insecticides and nerve gas?

Answer 21

aging means that after a few hours of exposure, the binding of these toxins to AChE is irreverisble

Question 22

what drug can be used to prevent irreversible binding of AChE inhibitors if given soon enough (within 1-2 hours)?

Answer 22

pralidoxime (2-PAM)

Question 23

what is usually the cause of death for people who die of AChE inhibitor poisoning? how is poisoning treated?

Answer 23

respiratory paralysis; poisoning treated by atropine to antagonize the muscarinic (parasympathetic) effects and pralidoxime if it is soon enough, to prevent irreverisble binding of AChE

Question 24

Which of the following is NOT an effect of activation of the muscarinic receptor?

A. contraction of the sphincter of the eye (miosis)
B. contraction of detrussor muscle
C. bronchoconstriction
D. decreased secretion of glands
E. accommodation for near vision

Answer 24

D. You would see an increased secretion of glands. All of these are parasympathetic responses

Question 25

what clinically important muscarinic agonist is used in the treatment of urinary retention?

Answer 25

bethanechol

for overactive bladder or urinary incontinence, antagonists such as tolterodine, oxybutynin, and solifenacin are used

Question 26

what drugs are used in the treatment of a glaucoma attack, that work by constricting the pupil and allowing for aqueous fluid to drain from the eye?

Answer 26

bethanechol, carbachol, pilocarpine

Question 27

in addition to having anithistamine properties, this drug is also used for its antimuscarinic properties

Answer 27

diphenhydramine (tricyclic antidepressants, especially amitriptyline, also have antimuscarinic properties)

Question 28

muscarinic receptor antagonists like atropine (belladonna) differ mainly in their pharmacokinetic properties; importantly, whether or not they have the ability do do what?

Answer 28

cross the blood-brain barrier

Question 29

All of these except which are anti-muscarinic effects?

A. Dry mouth
B. Mydriasis (dilated pupils)
C. Hypothermia
D. Tachycardia
E. Sedation (if drug crosses the blood-brain barrier)
F. Urinary retention and constipation
G. Hallucinations (if drug crosses the blood-brain barrier)

Answer 29

C. Remember that anti-muscarinic effects are anti-parasympathetic effects (ie, they will look like sympathetic effects). Hyperthermia, not hypothermia, would be one of these effects.

Question 30

what are the two primary clinical uses of atropine?

Answer 30

treatment of severe bradycardia;

treatment of AChE inhibitor poisoning

Question 31

in addition to atropine, name 3 other clinically important muscarinic antagonists

Answer 31

scopolamine - treats motion sickness, sedative

glycopyrrolate - dry up secretions during surgery (no CNS penetration)

benzatropine - treats parkinsonism

Question 32

muscarinic antagonist used to dilate your pupils during an eye exam

Answer 32

tropicamide

Question 33

anti muscarinic indicated in the treatment of asthma and COPD, marketed as an inhaler together with albuterol

Answer 33

ipratropium

Question 34

anti muscarinic indicated in the treatment of COPD, whose capsules are pierced and placed into a special inhalation device

Answer 34

tiotropium

Question 35

class of drugs that is useful in treating antimuscarinic overdose

Answer 35

AChE inhibitors

Question 36

______ is a nonselective agonist of all adrenergic receptors, including the major subtypes α1, α2, β1, β2, and β3. i

Answer 36

epinephrine

Question 37

_____ is a nonselective agonist that mediates its effects on α1, α2, and β1 receptors, stimulating increased heart rate, contractility, and vasoconstriction.

Answer 37

norepinephrine