Ch. 10: Cholinergic Drugs

Question 1

what do anticholinesterase agents do? How do they differ from antagonists?

Answer 1

block the degradation of Ach. Their action is similar to direct-acting agonists, just indirect. Differ from antagonists in that they do not interact with/block receptor

Question 2

T/F: atropine comes from natural sources

Answer 2

T

Question 3

Primary NT of parasympathetic side of ANS

Answer 3

Ach

Question 4

2 broad classes of receptors that Ach works on

Answer 4

nicotinic and muscarinic

Question 5

primary mech. of transmission between somatic motor neuron and target skeletal muscle

Answer 5

Ach action on nicotinic receptors

Question 6

major sites where Ach actions are mediated via muscarinic receptors***

Answer 6

CNS and visceral organs. “recognize that agents that act on muscarinic receptors can also act on CNS”

Question 7

what receptors does carbechol act on?

Answer 7

nicotinic and muscarinic

Question 8

N-butylammonium come from natural source?

Answer 8

yes

Question 9

bethanechol natural or synthetic?

Answer 9

synthetic

Question 10

bethanechol acts on what receptor(s)?

Answer 10

muscarinic (selective)

Question 11

carbechol acts on what receptor(s)?

Answer 11

muscarinic and nicotinic (nonselective)

Question 12

Acetylcholine acts on what receptor(s)?

Answer 12

muscarinic and nicotinic (nonselective)

Question 13

2 broad classifications of cholinergic receptors?**

Answer 13

muscarinic and nicotinic

Question 14

T/F: all cholinergic receptors are stimulated by Ach?

Answer 14

T

Question 15

muscle relaxants typically target what receptors?

Answer 15

nicotinic receptors in skeletal muscle

Question 16

what are muscarinic receptors stimulated by?

Answer 16

natural alkaloid muscarine

Question 17

what are nicotinic receptors stimulated by?

Answer 17

natural plant alkaloid nicotine

Question 18

What does SLUD stand for? What causes it?

Answer 18

salivation, lacrimation, urination, defecation. Caused by excess parasympathetic nervous system stimulation

Question 19

Ach is a physiological antagonist of what NT?***

Answer 19

NE and EP

Question 20

A MAJOR consequence of PS activation or mAChR stimulation

Answer 20

GI stimulation (motility, secretions, relaxation of sphincters)

Question 21

T/F: horses are very susceptible to Anticholinergic drugs

Answer 21

T

Question 22

What are prokinetic agents? What are they used for?

Answer 22

cholinergic agonists. Good for tx of constipation, impaction

Question 23

What are spasmolytics/antispasmotics? What are they used for?

Answer 23

anticholinergics (cholinergic antagonist). Tx of GI spasms

Question 24

parasympathetic stimulation of mAChR receptors promotes/inhibits secretions from most secretory glands?

Answer 24

promotes

Question 25

What agents promote stimulation of secretory glands?

Answer 25

cholinergic agonists and AchE agents

Question 26

Do anticholinergic drugs promote or inhibit stim. of secretory glands? What is a clinical problem of this?

Answer 26

inhibit. Can interfere with normal sweating, leading to hyperthermia in warm environments

Question 27

What is a rationale for using anticholinergic agents during anesthesia?**

Answer 27

to counteract increased respiratory tract secretions, bronchoconstriction, and respiratory center inhibition from drugs that activate muscarinic receptors on parasympathetic side

Question 28

muscarinic activation --> respiratory system

Answer 28

bronchoconstriction

Question 29

muscarinic activation via agonist --> eye

Answer 29

-pupil constriction

Question 30

muscarinic activation via antagonist --> eye

Answer 30

pupil dilation

Question 31

mAChR activation causes 2 main mechanical changes in eye

Answer 31

contraction of sphincter muscle and ciliary muscle

Question 32

mAChR activation --> cardiac tissue

Answer 32

decreased HR, with reduced contractility and impulse conduction to a lesser extent. Due to increased K conductance in pacemaker cells

Question 33

mAChR activation --> blood vessels

Answer 33

vasodilation, decreased BP

Question 34

Where does most parasympathetic innervation to blood vessels lie?

Answer 34

on the endothelial cells surrounding vessels, NOT on the vascular smooth muscle of the vessel itself

Question 35

Carbachol

Answer 35

- cholinergic agonist - mixed N/M agonist - not used anymore; very potent; GI stimulant and bladder contraction - resistant to cholinesterase degredation

Question 36

Bethanechol

Answer 36

- cholinergic agonist - muscarinic agonist - less potent than carbachol - GI stimulant, contract bladder - resistant to AChE deg.

Question 37

contraindications of bethanechol

Answer 37

known urinary tract obstruction, GI obstruction, asthma, resp. disease, GI ulcers

Question 38

What is the purpose of combining bethanechol with an alpha-adrenergic blocking agent?

Answer 38

contraction of sphincter is inhibited while contraction of smooth muscle inside the bladder is stimulated; helps void the bladder

Question 39

pilocarpine

Answer 39

natural muscarinic agonist. Used to treat glaucoma and KCS

Question 40

3 natural muscarinic agonists

Answer 40

muscarine, pilocarpine, arecoline

Question 41

treat SLUD syndrome with:

Answer 41

atropine w/wo EP and support

Question 42

contraindications of cholinergic agonists**

Answer 42

``` asthma,COPD, pulm. dz GI/urinary tract obstruction GI ulcer hyperthyroidism coronary insufficiency pregnancy ```

Question 43

atropine is a mild CNS depressant/stimulant

Answer 43

depressant. It is a cholinergic antagonist

Question 44

T/F: atropine crosses BBB

Answer 44

True!

Question 45

N-butylscopolammonium Bromide

Answer 45

- cholinergic (competitive) antagonist - targets muscarinic receptors - antispasmotic agent, aid for rectal exam - no BBB cross

Question 46

Glycopyrrolate

Answer 46

- cholinergic antagonist - targets muscarinic receptors - similar but less potent than atropine

Question 47

Summary of therapeutic uses for anti-cholinergic agents**

Answer 47

- reduce smooth muscle spasms - antisecretory - ophthalmic exams: pupillary dilation - reduces cardiodepressant effects of other drugs - antidotes for mushroom poisoning and anticholinesterases

Question 48

Side effects of cholinergic antagonists**

Answer 48

- dry mouth - tachycardia - mydriasis - hyperthermia - GI stasis - ataxia - delerium - convulsions - resp. depression - amnesia