Lecture 38 Flashcards Preview

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1

What are the two types of cholinergic drugs?

cholinergic agonists and cholinergic antagonists

2

What are the two types of cholinergic agonists?

direct acting- bind to and activate

indirect acting- inhibit

3

What are the direct effects of ACh on the cardiovascular system?

1. vasodilation (M3)

2. decrease in cardio rate (M2)

3. decrease in the rate of conduction by SA and AV nodes (M2)

4. decrease force in contraction (M2)

4

How does a low dose of ACh impact the cardiovascular system?

A fall in blood pressure, but tachycardia occurs in response

5

How does a high does of ACh impact the cardiovascular system?

leads to a fall in blood pressure (M3) and bradycardia (M2)

6

How does ACh impact the vasculature?

release of NO and vasodilation

lower BP

7

How does ACh impact the eye?

miosis

8

How does ACh impact the ciliary muscle?

accommodation of lens to near vision

9

How does ACh impact glands?

increase secretion

10

how does ACh impact the bronchi?

constriction

11

how does ACh impact the heart?

decreased heart rate and conduction velocity

12

how does ACh impact the GI?

increased peristalic activity and relaxtion of sphincters

13

how does ACh impact the bladder?

Contraction of detrusor muscle; relaxation of
sphincter

14

What does atropine do?

a muscarinic antagonist

If muscarinic effects are blocked by a muscarinic antagonist such as atropine, large doses of acetylcholine produce nicotinic effects:

Vasoconstriction and increase in blood pressure

15

What are the two kinds of direct-acting cholinergic agonists?

1. esters of choline

2. alkaloids

16

What are examples of choline esters?

1. acetylcholine

2. methacholine

3. bethanechol

17

About choline esters?

they are quaternary ammoniums

poorly absorbed and distributed into the CNS

ACh is very rapid hydorlyzed

meth and beth are more resistant to hydrolysis

18

Acetylcholine

A muscarinic receptor and nicotinic agonist

used to produce an miosis effect during cataract surgery or other procedures where miosis is needed

19

Bethanechol

muscarinic agonist

uses:

1. postoperative urinary retention
2. atony of the bladder

20

methacholine

Muscarinic agonist

uses:
Diagnosis of bronchial airway hyperreactivity in
subjects who do not have clinically apparent
asthma.

21

What are the natural alkaloids (direct acting)?

1. pilocarpine

2. nicotine

22

pilocarpine?

partial muscarinic agonist
tertiary amine
stable to hydrolysis by ACh enzyme

uses:
glaucoma
dry mouth due to radiotherapy

23

what are the adverse effects of muscarinic agonists?

1. sweating
2. salivation
3. flushing
4. low bp
5. nausea
6. abdominal pain
7. diarrhea
8. bronchospasm

24

nicotine?

tertiary amine
agonist at nicotinic receptors

Depending on the dose, nicotine depolarizes
autonomic ganglia, resulting first in stimulation
and then in paralysis.

25

low nicotine dose?

ganglionic stimulation by depolarization

26

high nicotine dose?

ganglionic and neuromuscular blockade

27

nicotine uses?

to stop smoking

28

indirect-acting cholinergic agents?

1. edrophonium

2. carbamates

3. organophosphates

29

mechanism of edrophonium?

binds reversibly to the active site
of the enzyme. The inhibition is short-lived.

anticholinesterase

30

mechanism of carbamates?

form a covalent bond with the enzyme

anticholinesterase