EXAM #1: AND PHARMACOLOGY - ADRENERGIC Flashcards Preview

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Flashcards in EXAM #1: AND PHARMACOLOGY - ADRENERGIC Deck (54)
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1
Q

What is the rate limiting step in catecholamine synthesis? What enzymes catalyzes this reaction?

A

Tyrosine–>DOPA, which is catalyzed by the enzyme “Tyrosine Hydroxylase”

2
Q

What drug blocks the conversion of Tyrosine to DOPA?

A

Metyrosine

3
Q

How are synthesized catecholamines transported into vesicles?

A

VMAT (vesicular monoamine transporter)

4
Q

What drug blocks VMAT?

A

Reserpine

5
Q

Clinically, how is reserpine used?

A

To treat resistive HTN

6
Q

What facilitates binding of vesicles containing catecholamines to the nerve terminal membrane?

A

VAMPs

7
Q

What drug blocks VAMPs?

A

Bretyilum

8
Q

What are the three methods that terminate catecholamine action?

A

1) Simple diffusion
2) Neuronal reuptake
2) Extra-neuronal uptake

9
Q

What enzyme metabolizes catecholamines that diffuse into the circulation?

A

COMT

“Catechol-O-methyl-transferase”

10
Q

What transporter facilitates the neuronal reuptake of NE?

A

NET1

11
Q

What drugs can inhibit NET1? What is the effect of these drugs?

A
  • Cocaine
  • Tricyclic antidepressants

These drugs increase the concentration of NE in the synaptic cleft

12
Q

What are the analogs to NET for DA and 5-HT?

A

DAT

SERT

13
Q

What transporter facilitates extraneuronal reuptake of catecholarmines? What drugs can block these transporters?

A
  • ENT/ NET2

Corticosteroids can block these transporters.

14
Q

What is the fate of catecholamines that have been reuptaken into a nerve terminal?

A

1) Restored in vesicles for release
2) Metabolism by monoamine oxidase (MAO)

Note that there are two isoforms of MAO, MAO-A and MAO-B.

  • MAO-A= NE, 5-HT, and tyramine
  • MAO-B= DA
15
Q

What drug can inhibit MAO?

A

Phenelzine

16
Q

Draw the mechanisms G-protein linked second messenger activation.

A

p. 244 First Aid

17
Q

What is the mnemonic to remember the receptor types and their associated g-protein class?

A

“Qiss and qiq till you’re siq of sqs.”

18
Q

Outline the mnemonic to remember the receptor types and their associated g-protein class.

A

p. 244 First Aid

19
Q

List the Gq-coupled receptors. What is the mnemonic to remember these receptors?

A
H1
Alpha-1 
V1 
M1 
M3 

“HAVe 1 M and M”

20
Q

List the Gs-coupled receptors.

A
B1
B2
D1
H2 
V2
21
Q

List the Gi-coupled receptors. What is the mnemonic to remember these receptors?

A

M2
Alpha-2
D2

“MAD 2s”

22
Q

Where are alpha-1 receptors located?

A

Vascular smooth muscle

  • Arterioles
  • Veins

Radial (dilator) muscle of the eye

Bowel and bladder sphincters

  • Bladder trigone and sphincter
  • Male sex organ

Liver
Kidney

23
Q

What is the consequence of alpha-1 activation in the eye?

A

Contraction–>mydriasis

24
Q

What is the effect of alpha-1 activation in the arterioles?

A

Contraction leading to:

  • Increased TPR
  • Increased diastolic pressure
  • Increased afterload
25
Q

What is the effect of alpha-1 activation in the veins?

A

Contraction leading to:

  • Increased venous return
  • Increased preload
26
Q

What is the effect of alpha-1 activation in the bladder trigone and sphincter?

A

Contraction leading to urinary retention

27
Q

What is the effect of alpha-1 activation in the male sex organ?

A

Ejaculation

28
Q

What is the effect of alpha-1 activation in the liver?

A

Increased glycogenolysis

29
Q

What is the effect of alpha-1 activation in the kidney?

A

Decreased renin release

30
Q

List the locations of alpha-2 receptors.

A

Prejunctional nerve terminals
- Decreased SNS output

Platelets
- Aggregation

Pancreas

  • Decreased insulin release
  • Decreased lipolysis
31
Q

What is the effect of alpha-2 activation in the prejunctional nerve terminal?

A

Decreased NE synthesis and release

32
Q

What is the effect of alpha-2 activation in the platelets?

A

Platelet aggregation

33
Q

What is the effect of alpha-2 activation in the pancreas?

A

Decreased insulin secretion

34
Q

List the locations of B1 receptors.

A

Heart

  • Increased rate
  • Increased contractility

Kidney
- Increased renin release

Increased lipolysis

35
Q

What is the effect of Beta-1 activation in the heart?

A

SA Node= positive chronotrope

AV node= positive dromotrope

Atrial and ventricular muscle=

  • positive ionotrope
  • increased conduction velocity, CO, and O2 consumption
36
Q

What is the effect of Beta-1 activation in the kidney?

A

Increased Renin release

37
Q

List the locations of Beta-2 receptors.

A
  • Heart= increased rate and contractility
  • Liver= increased lipolysis
  • Pancreas= Increased insulin release
  • Eye
    1) Ciliary epithelium= aqueous humor production
    2) Ciliary m.= relaxation
  • Vascular smooth muscle= vasodilation
  • Bronchioles= bronchodilation
  • Uterus= decreased uterine contraction
38
Q

What is the effect of Beta-2 activation in the vasculature?

A

Vasodilation leading to:

  • Decreased TPR
  • Decreased diastolic BP
  • Decreased afterload
39
Q

What is the effect of Beta-2 activation in the uterus?

A

Relaxation

40
Q

What is the effect of Beta-2 activation in the bronchioles?

A

Bronchodilation

41
Q

What is the effect of Beta-2 activation in the skeletal muscle?

A
  • Glycogenolysis

- Muscle contraction/ tremors

42
Q

What is the effect of Beta-2 activation in the liver?

A

Glycogenolysis

43
Q

What is the effect of Beta-2 activation in the pancreas?

A

Insulin secretion

44
Q

What is the effect of muscarinic stimulation of the eye?

A

Stimulation of M receptors causes:

1) Miosis (sphincter m.)
2) Spasm of accomodation and opening the Canal of Schlemm

45
Q

What is the result of muscarinic blockade on the eyes?

A

1) Mydriasis

2) Paralysis of accommodation, or “cycloplegia”

46
Q

What is the effect of sympathetic alpha-1 stimulation on the eye?

A

Myrdiasis

47
Q

How does the mydriasis caused by adrenergic stimulation differ from that caused by muscarinic stimulation?

A

Alpha-1= pupillary radial muscle; thus, there is NO cycloplegia

Muscarinic= mydriasis WITH cycloplegia b/c of effects of ciliary m.

48
Q

Where are D1 receptors located?

A

Renal, mesenteric, and coronary vasculature

49
Q

What is the effect of D1 stimulation?

A

Vasodilation

In the kidney, this leads to:
- Increased GFR, RBF and Na+ excretion

50
Q

Draw the autonomic feedback loop controlling arterial blood pressure. Draw the hormonal ANS feedback loop controlling blood pressure.

A

N/A

51
Q

What is the meeting point between the autonomic and hormonal feedback loops controlling blood pressure?

A

Mean Arterial Pressure (MAP)

52
Q

What will changes in the MAP evoke?

A

Powerful homeostaic responses

Note that if a drug has induced a change in MAP, homeostatic responses to that change may produce the OPPOSITE action of the intended drug,

53
Q

What is reflex bradycardia?

A

Reflexive lowering of heart rate in response to an increase in MAP or increase in TPR–>increase in MAP

54
Q

What is reflex tachycardia?

A

Reflexive raising of heart rate in response to a decrease in TPR–>decrease in MAP

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