Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Cardio Week 2 > Lecture 21: Cardiovascular Effects of Autonomic AGONISTS > Flashcards

Lecture 21: Cardiovascular Effects of Autonomic AGONISTS Flashcards

(60 cards)

Start Studying
1
Q

How to understand this lecture’s material?

A
  1. Know the location and actions of cardiovascular muscarinic and adrenergic receptors
  2. Know a particular compound’s activities on these receptors
  3. Understand how the compound’s various actions on the CV system’s components to determine its overall performance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Where are the muscarinic receptors located?

A

In the SA, AV nodes and atrial muscle (not the ventricle)
Long preganglionic fibers
Short Postganglionic fibers
Neurotransmitter at the ganglia and the organs are both acetylcholine
Parasympathetic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Where are the adrenergic receptors located?

A 
Heart, kidney, arterioles
Short preganglionic fibers
Long postganglionic fibers
Ach for ganglia
NE for organs
Sympathetic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the two types of receptors in the parasympathetic?

A
  1. muscarinic (1,2)

2. nicotinic (1,2)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the two receptors of recepotrs in the sympathetic?

A
  1. alpha (1,2)

2. beta (1,2)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the two parasympathetic agonists?

A
  1. Edrophonium

2. Acetylcholine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the effects of muscarinic receptors on the heart?

A
  1. Decreases heart rate
    i. decrease SA node conduction
    ii. increased AV node refractoriness
  2. Decreases inotropy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the CV response to a generalized parasympathetic discharge?

A

Vagal reaction or faint
Decrease in SA nodal automaticity, decrease in AV nodal conduction (profound bradycardia)
Decrease in systemic arteriolar resistance due to vasodilation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How is the vagal reaction/faint response provoked?

A
  1. may be provoked by fear or pain

2. may be provoked by inappropriate sensitivity of the carotid sinus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Does acetylcholine agonists have any significance?

A

No because they are rapidly degraded by AChE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is Edrophonium?

A

MoA: AChE inhibitor
Indirectly stimulates parasympathetic activity
Ultra short acetylcholine esterase inhibitor
AKA: Tensilon, Reversol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the side effects of edrophonium?

A

Also causes profound abdominal cramping by stimulating contraction of GI smooth muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the clinical uses of Edrophonium?

A
  1. Used to counter increased HR such as supraventricular tachycardias
    • have been replaced by adenosine due to the side effects
  2. helps diagnose myasthenia gravis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are examples long acting acetylcholine esterase inhibitors?

A
  1. Sarin
  2. Parathiion and malathion (insecticides)
  3. physostigimine, neostigmine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are principles for understanding the overall actions of adrenergic agonists?

A
  1. agonists differ in their relative activities at the various adrenergic receptor types
  2. overall action determined by
    i. agonists POTENCY for each receptor type
    ii. organ’s DENSITY of each receptor type
  3. overall action is determined by concentration of agonist (route of administration) as well as interaction of drug induced alterations on each interrelated organ’s function
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the adrenergic receptor types?

A

A1, A2, B1, B2, B3

Alpha receptors are NOT located in the heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Where are Alpha1 receptors found?

A

i. vascular smooth muscle (constrictor)

ii. Genitourinary smooth muscle (constrictor)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Where are Alpha2 receptors found

A
  1. vascular smooth muscle (constrictor)

2. platelet aggregation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Where are Beta1 receptors found?

A

i. heart (myocardium-inotropy & specialized tissues-chronotropy)
ii. Kidney (juxtaglomerular cells-renin secretion)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Where are Beta2 receptors found?

A

i. vascular smooth muscle (dilator)

ii. airway smooth muscle (dilator)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Where are Beta 3 receptors found?

A

i. adipose tissue (lipolysis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the CV actions of B1 receptors?

A 
Increase heart rate by
	i. increasing impulse formation
	ii. decreasing refractoriness
	iii. increasing velocity
Increases myocardial inotropy
Increases renin secretion in kidney (which leads to retention of fluid)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the CV actions of alpha 1 receptors?

A
  1. Arteriolar vasoconstriction of skin, GI and kidney

2. Large venous constriction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are CV actions of Beta 2 receptors?

A

Arteriolar vasodilation of heart, skin and skeletal muscle

Airway dilation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What are the types of adrenergic agonists?
1. Endogenous agonists i. Epi ii. NE iii. Dopamine 2. Synthetic agonists i. Phenylephrine ii. Dobutamine iii. Isoproterenol
26
What receptors does NE bind to?
Beta 1 and alpha; NO beta 2 activity
27
What receptors does epinephrine bind to?
Beta 1, Beta 2 and alpha
28
What receptors does dopamine bind to?
Beta 1, Alpha and delta 1,2; NO beta 2 activity
29
What is Mean Arterial pressure (MAP)?
MAP = CO x SVR (systemic vascular resistance)
30
What are the key characteristics of epinephrine?
MoA: MIXED alpha, beta1 and beta2 agonist Increased systemic arterial pressure and thus increased CO and SVR (per MAP equation) Increased heart rate
31
What are the indications of epinephrine?
1. Cardiac Arrest 2. Anaphylaxis 3. hypotension/bradycardia
32
What is epinephrine contraindicated with?
1. arrhythmias | 2. narrow angle glaucoma
33
What are the side effects of epinephrine?
1. cardiac arrhythmias 2. tachycardia excitation 3. tremulousness 4. insomnia, nervousness 5. palpitations
34
What are the key characteristics of norepinephrine?
MoA: Mixed alpha, beta 1 agonist with LITTLE beta2 activity Increase systemic vascular resistance Eventually, heart rate is decreased because beta1 activity is opposed by strong alpha action to increase SVR -increase SVR without B2 vasodilation means baroreceptors will tell heart to slow down Cardiac ouput is UNCHANGED
35
What are the indications for NE treatment?
1. Refractory hypotension especially due to sepsis | Not used to treat anything that requires greater cardiac output
36
What are the side effects of NE?
1. ischemic injury 2. bradycardia (due to baroreceptor reflex) 3. substernal pain
37
What are the key characteristics of dopamine?
MoA: alpha, beta1, delta1 agonist with LITTLE beta 2 activity Is does dependent Has delta1 dopaminergic activity at low doses i. Low dose = isolated delta1 action = renal VASODILATION (“renal dose dopamine”) ii. intermediate dose = beta1 action combines with delta 1 action to increase cardiac output with minimal effect of systemic vascular resistance iii. high dose = alpha action overwhelms the gamma1 actiona nd the effect is similar to norepinephrine
38
What are the effects of dopamine at low doses?
Isolated delta 1 reaction Produces predominately renal vasodilation “Renal Dose Dopamine” = smallest dose
39
What are the effects of dopamine at intermediate doses?
Beta1 action combines with delta 1 to increase cardiac output (since heart rate won’t be decreased due to adequate renal perfusion) Does NOT effect SVR
40
What are effects of dopamine at high doses?
1. alpha action overwhelms the delta1 action and the effect is similar to norepinephrine (no change in CO and decrease in HR)
41
What is the significance of dopamine for CV therapy?
Dopamine is an effective PRESSOR which, in low to intermediate doses, does not reduce renal blood flow
42
What are the indications of dopamine use?
1. Cardiogenic shock 2. Severe cardiac failure 3. Hypotension that leads to decreased renal blood flow 4. Can be used in sepsis Use dopamine at low to intermediate doses!
43
What are the contraindications of dopamine?
Ventricular arrhythmias, sever AS, pheochromocytoma
44
What is pheochromocytoma?
Neuroendocrine tumor that leads to excessive production of catecholamines Tumor in adrenal medulla
45
What are the alpha-selected adrenergic agonists?
Phenylephrine
46
What are the betaadrenergic agonists?
1. isoproterenol | 2. dobutamine
47
What are the key characteristics of phenylephrine?
MoA: binds predominately to alpha receptors 1. Increase SVR 2. decrease heart rate (due to baroreceptor reflex) 3. decrease CO Similar to NE effect (minus the CO decrease)
48
What are the indications of phenylephrine?
Sepsis | Hypotension
49
What are the side effects of phenylephrine?
May lead to cardiac ischemia, vascular ischemia and angina
50
What are the key characteristics of isoproterenol?
MoA: binds to beta 1 and beta 2 receptor with little alpha activity 1. Decrease in SVR 2. increase in HR 3. Increase in CO
51
What are the indications for isoproterenol?
1. heart block 2. stimulate myocardial contraction after heart surgery 3. treatment of beta-blocker overdose
52
What are the side effects of isoproterenol?
1. tachyarrhythmias 2. palpitations 3. nervousness 4. hyper and hypotension??
53
What are the key characteristics of dobutamine?
MoA: binds to B1 receptor - clinical preparation is a racemic mixture (+ enantiomer = antagonist and – enantiomer is agonist) 1. beta 1 activity is predominantly INOTROPIC with modest chronotropic activity - modest beeta2 activity, therefore relatively little effect on blood pressure 2. Increase in CO
54
When you need a drug to increase inotropy but only modest increase in chronotropy, what do you use?
Dobutamine
55
What are the indications for dobutamine?
Circulatory support for congestive heart failure MI Something requiring inotropic support
56
What are the side effects of dobutamine?
Ventricular arrhythmias
57
What are the clinical uses of adrenergic agonists?
Adjunctive treatment of shock | Supports patient until underlying cause can be found
58
What is selection of a drug based upon?
1. heart rate/rhythm 2. afterload 3. preload 4. contractility
59
What adrenergic agonist would you use to treat septic shock?
Septic shock = decreased SVR and increased CO Drug wants to increase SVR and decrease CO (primarily Alpha receptor agonists) 1. Norepinephrine 2. Phenylephrine Can use dopamine too as suggested in notes
60
What adrenergic agonist would you use for cardiogenic shock?
Low CO in this case with high MAP Thus you want to increase contractility WITHOUT increased blood pressure as well Drug needs to be pure Beta1 agonist DOBUTAMINE Can use dopamine too as suggested in notes

Cardio Week 2 (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions