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26 Cards in this Set
- Front
- Back
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VIP
Describe the formation of angiotensin. |
Angiotensin is formed by the action of renin on angiotensinogen releasing angeotensin I, a decapeptide. Angiotensin I is converted to Angiotensin II, an octapeptide by the action of converting enzyme. Angiotensin II is degraded into inactive peptide by the action of angiotensinases (KEY). Of these angiotensin I, II, and III, only angiotensin II is active and produces profound vasoconstrictive responses.
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What is the effect of ACE?
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Converts Angiotensin I into II
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VIP
What two drugs are known as angiotensin converting enzyme inhibitors (ACE inhibitors) |
Captopril
Enalapril |
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Levels of what are increased during pregnancy?
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Angiotensinogen (due to hypertension)
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VIP VIP
What is the exact same as ACE? (two names) |
1. peptidyl dipeptidase
2. kininase II |
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VIP VIP
What does ACE do? |
Catalyzes the cleavage of dipeptide from the carboxyl terminal of angiotensin I (decapeptide) into angiotensin II (octapeptide). This enzyme is widely distributed in the vasculature and is a target for antihypertensive drugs
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VIP VIP
What hormone is 40 times more potent that norepi at producing vessel contraction? |
Angiotensin II
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What two things does Angiotenson II stimulate from the adrenal glands?
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Adrenal medulla - release of epi and norepi
Adrenal cortex - release of aldosterone |
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Does angiotensin II contribute to cardiac hypertrophy?
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Yes, it has mitogenic effects on the vascular and cardiavascular muscle cells.
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VIP
What would blocking the secretion of renin do to angiotensin II? |
A decrease in renin would cause an inhibition in angiotensin I production and thus decrease angiotensin II formation
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VIP
Explain how blocking ACE (via ACE inhibitors) can lead to side effects such as cough, angioedema, and hypotensive shock? |
ACE inhibitors not only block conversion of angio I to II - they also inhibit the degration of vasopeptides like BRADYKININ, SUBSTANCE P, and ENKEPHALIN. These, bradykinin especially, causes profound hypotension and cough
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VIP
Thought the clinical benefits of ACE inhibitors and angiotensin receptor inhibitors are almost the same, what is one important difference? |
Angiotensin receptor inhibitor can be given to septic patient with hypertension because it does not inhibit ACE.
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What are the two angiotensin receptor inhibitors?
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Losartan
Valsartan |
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VIP
What are bradykinins? |
Bradykinins are one of the most potent vasodilators produced by the endogenous actions of enzymes known as KALLIKREINS and kininogenases.
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Why does pain, swelling, and an inflammatory response result from some wasp bites?
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Because the wasps released kinins
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VIP VIP
What are KALLIKREINS? |
Kallikreins are glycoprotein enzymes produced in the liver as prekallikreins and are present in plasma and several tissues including the kidney, pancreas, GI tract, sweat glands, and salivary glands.
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VIP VIP VIP
What is the Flecher factor (aka)? What does it promote? |
Flectcher factor is also called Plasmatic prekallikrein and it promotes the coagulation process via intrinsic system. Plasma prekallikrein can be activated by trypsin. The active kallikrein can generate kinins and exert a profound action on hemodynamics (hypotension)
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What do patients with DIC almost always have (that is thought to cause the DIC)?
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An increased kallikrein production
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Draw the kallikrein-kinin system:
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p.5 Vasoactive peptides
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VIP
What is the function of kininogen? (specifically high molecular weight kininogen) |
The HMWK (aka Fitzgerald factor) is involved in the promotion of coagulation processes in the intrinsic factor. Plasma kallikrein cleaves the HMWK to generate bradykinin.
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What is bradykinin released by?
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Plasma kallikrein
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What does Aprotonin do?
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It is a Kallikrein inhibitor and thus it prevents the formation of Kallikrein and so bradykinin generation is blocked.
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VIP
What is endothelins? |
Endothelins are potent vasoconstricting peptides that were first found in arotic endothelial cells.
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What is Bosentan?
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An non-selective antagonist of endothelin
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What is the function of vasoactive intestinal peptide?
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VIP produces marked vasodilation
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What is the function of Substance P?
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It induces vasodilation by stimulated release of nitric oxide
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