L35 Pharmacology of Vasoactive Peptides Flashcards
What are the most important vasoactive peptides?
- Angiotensins
- Bradykinin
- Vasopressin
- ANP
- Endothelins
Vasoactive peptides act on ___ receptors.
Cell surface (many are G-protein coupled)
Discuss the process of formation of angiotensins.
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.
What increases antiogensinogen production?
Corticosteroids, estrogens, thyroid hormones, and angiotensin II
What are the sizes of Angiotensin I, II, and III?
I: Decapeptide
II: Octapeptide
III: Heptapeptide
Angiotensin convertying enzyme is also known by what two other names?
- Peptidyl dipeptidase
2. Kininase II
Which form of Angiotensin is active?
II
What are the effects of Angiotensin II?
Vasoconstriction (causes hypertension)
How can angiotensin be inhibited?
- Blocking renin secretion/action
- Blocking the conversion of I to II (via ACE)
- Blocking angiotensin receptors
What do ACE inhibitors do?
Block conversion from I to II AND inhibit degradation of bradykinin (a vasodilator)
What are the two ACE inhibitors?
Captopril and Enalapril
What are the two angiotensin receptor antagonists?
Losartan and Valsartan
What is a potent group of vasodilator peptides?
Kinins
What enzymes produce kinins?
Kallikreins
___ are glycoprotein enzymes produced in the liver as pre-___ and are present in various parts of the body.
Kallikreins
Plasmatic prekallikrein is also known as ___. This promotes coagulation via the ___ system. It can also be activated by factor ___.
Fletcher factor; intrinsic; 12a
Active kallikrein can generate ___ after being activated by ___.
Kinins; trypsin
In addition to vasodilatory effects, kinins also promote ___.
Algesia
The biologic actions of kinins are mediated by specific receptors localized on the membranes of the target tissue. What are the two types?
B1: predominant receptors
B2: the antagonist we have (Icatibant) targets this receptor
What metabolizes kinins?
Kininase I and II (Kininase II = ACE)
How is kallikrein inhibited (thus blocking bradykinin generation)?
Aprotonin
___ is also known to block the algesic effects of prostaglandins generated by bradykinin.
Aspirin
What is vasopressin?
Anti-diuretic hormone that increases water resoprtion (short term vasoconstriction)
What are the current analogues of vasopressin that have been developed?
Desmopressin
What does desmopressin do?
Increases factor 8 activity of patients with mild hemophilia and VW disease and is effective in controlling the bleeding in mild surgical procedures
What do natriuretic peptides do?
Diuretic and vasorelaxant
Vasopeptide inhibitors inhibit ___. This leads to an increase in levels of natriuretic peptides and decrease formation of angiotensin II.
Metaloproteases
What are the 3 vasopeptide inhibitors?
Omapatrilat, sampartilat, and fasidotrilat
Endothelins have potent ___ properties.
Vasoconstricting
What is the non-selective antagonist of endothelin?
Bosentan
