Renin-Angiotensin-Aldosterone System

• BP
• blood volume

fluid & electrolyte balance

angiotensin converting enzyme

vasoconstriction

stimulation of aldosterone release

--> raise BP

can act on heart /blood vessels to cause hypertrophy/remodeling (redistribution of mass)

Direct: effects arterioles more than veins -> raises BP

Indirect: release of E/NE, acts on CNS to increase sympathetic stimulation of blood vessles

• works on DCT of kidney
• retain sodium -> retains water
• -> raises blood volume/pressure

constriction of renal vessels -> less GFR

release of aldosterone

• blood loss
• dehydration
• sodium depletion

• catalyzes formation of angiotensin I from angiotensinogen
• produced in kidneys

• hypertension, heart failure, diabetic nephropathy, myocardial infarction
• suppress formation of angiotensin II
• -> dilate blood vessels
• -> reduce blood volume 
• -> prevent/reverse pathologic changes in heart/vessels
• also produce bradykinin, promotes vasodilation

produce similar effects, but no single ACE inhibitor is approved to treat all conditions

lower arterial tone -> improve regional blood flow

reduce cardiac afterload -> increase cardiac output

venous dilation -> reduce pulmonary congestion/peripheral edema

dilate blood vessels in kidneys -> increase renal blood flow -> promote excretion of sodium and water

less blood volume -> less strain on heart

hypotension (after first dose)

hyperkalemia

cough

renal failure