L35 Pharmacology of Vasoactive Peptides

Question 1

What are the most important vasoactive peptides?

Answer 1

1. Angiotensins
2. Bradykinin
3. Vasopressin
4. ANP
5. Endothelins

Question 2

Vasoactive peptides act on ___ receptors.

Answer 2

Cell surface (many are G-protein coupled)

Question 3

Discuss the process of formation of angiotensins.

Answer 3

Angiotensinogen is coverted to Angiotensin I via Renin.

Angiotensin I is converted to Angiotensin II via ACE.

Angiotensin II is converted to Angiotensin III via Aminopeptidase.

Angiotensin III is broken down via Angiotensinases.

Question 4

What increases antiogensinogen production?

Answer 4

Corticosteroids, estrogens, thyroid hormones, and angiotensin II

Question 5

What are the sizes of Angiotensin I, II, and III?

Answer 5

I: Decapeptide
II: Octapeptide
III: Heptapeptide

Question 6

Angiotensin convertying enzyme is also known by what two other names?

Answer 6

1. Peptidyl dipeptidase

2. Kininase II

Question 7

Which form of Angiotensin is active?

Answer 7

II

Question 8

What are the effects of Angiotensin II?

Answer 8

Vasoconstriction (causes hypertension)

Question 9

How can angiotensin be inhibited?

Answer 9

1. Blocking renin secretion/action
2. Blocking the conversion of I to II (via ACE)
3. Blocking angiotensin receptors

Question 10

What do ACE inhibitors do?

Answer 10

Block conversion from I to II AND inhibit degradation of bradykinin (a vasodilator)

Question 11

What are the two ACE inhibitors?

Answer 11

Captopril and Enalapril

Question 12

What are the two angiotensin receptor antagonists?

Answer 12

Losartan and Valsartan

Question 13

What is a potent group of vasodilator peptides?

Answer 13

Kinins

Question 14

What enzymes produce kinins?

Answer 14

Kallikreins

Question 15

___ are glycoprotein enzymes produced in the liver as pre-___ and are present in various parts of the body.

Answer 15

Kallikreins

Question 16

Plasmatic prekallikrein is also known as ___. This promotes coagulation via the ___ system. It can also be activated by factor ___.

Answer 16

Fletcher factor; intrinsic; 12a

Question 17

Active kallikrein can generate ___ after being activated by ___.

Answer 17

Kinins; trypsin

Question 18

In addition to vasodilatory effects, kinins also promote ___.

Answer 18

Algesia

Question 19

The biologic actions of kinins are mediated by specific receptors localized on the membranes of the target tissue. What are the two types?

Answer 19

B1: predominant receptors
B2: the antagonist we have (Icatibant) targets this receptor

Question 20

What metabolizes kinins?

Answer 20

Kininase I and II (Kininase II = ACE)

Question 21

How is kallikrein inhibited (thus blocking bradykinin generation)?

Answer 21

Aprotonin

Question 22

___ is also known to block the algesic effects of prostaglandins generated by bradykinin.

Answer 22

Aspirin

Question 23

What is vasopressin?

Answer 23

Anti-diuretic hormone that increases water resoprtion (short term vasoconstriction)

Question 24

What are the current analogues of vasopressin that have been developed?

Answer 24

Desmopressin

Question 25

What does desmopressin do?

Answer 25

Increases factor 8 activity of patients with mild hemophilia and VW disease and is effective in controlling the bleeding in mild surgical procedures

Question 26

What do natriuretic peptides do?

Answer 26

Diuretic and vasorelaxant

Question 27

Vasopeptide inhibitors inhibit ___. This leads to an increase in levels of natriuretic peptides and decrease formation of angiotensin II.

Answer 27

Metaloproteases

Question 28

What are the 3 vasopeptide inhibitors?

Answer 28

Omapatrilat, sampartilat, and fasidotrilat

Question 29

Endothelins have potent ___ properties.

Answer 29

Vasoconstricting

Question 30

What is the non-selective antagonist of endothelin?

Answer 30

Bosentan