Wk 4 RAA

Question 1

Discuss the renin-angiotensin-aldosterone system and describe the role of each component

Answer 1

RAA - a major regulatory system in the body in maintaining body fluid homeostasis, ie blood pressure, fluid volume, electrolyte balance

Angiotensinogen-[Renin]→Angiotensin I-[ACE]→Angiotensin II→Aldosterone

> Angiotensinogen - produced by the liver
Renin - secreted by kidneys, drop in Na+ concentration → ↓BP
Angiotensin I - inactive molecule
Angiotensin II - vasoconstriction → ↑BP
Aldosterone - secreted by adrenal cortex, ↑Na+&H2O reabsorption, ↑K+ excretion

Question 2

Describe the actions of ACE inhibitors + Angiontensin II Receptor Antagonists (ARBs), understand their mechanism of action, and give representative examples

Answer 2

ACE inhibitors
- Captopril, ramipril, peridopril
- MOA: inhibit ACE + inhibit the breakdown of bradykinin
- Indication:
> hypertension
> chronic heart failure
> prevent kidney failure in Pt with high blood pressure/diabetes
> reduce risk of stroke
> improve survival after myocardial infarction
> diabetic nephropathy
- AEs: cough, hypotension, hyperkalemia, renal impairment
- CON: renal impairment, elderly, pregnancy

Angiotensin II receptor antagonist
- ibersartan, candersartan
- MOA:
> prevent angiotensin II from binding to type 1 angiotensin (AT1) receptors on blood vessels
> ↓ vasoconstriction, aldosterone release, sodium reabsorption
- Indication:
> hypertension
> chronic heart failure
> prevent kidney failure in Pt with high blood pressure/diabetes
> reduce risk of stroke
- AEs: cough, hypotension, hyperkalemia, renal impairment
- CON: renal impairment, elderly, pregnancy