B2 RAS

Question 1

The RAS regulates

Answer 1

1. BP & water balance
2. increases renal sympathetic nerve activity, decreases BP & GFR by renin secretion (–> Ang II)
3. increases BP

Question 2

define

1. circulating renin
2. Tissue renin
3. Where are components of the RAS found

Answer 2

1. Produced by JGC. Release controlled by BP, Na & sympathetic nerves
2. Produced locally or captured from circulation
   Components of the RAS found in heart, blood vessels and cardiovascular centres
   Components

Question 3

Actions of Ang II

Answer 3

Vasoconstriction
Stimulation of aldosterone secretion
Direct effect on kidney to cause Na+ and water retention = raised blood volume and BP.
Feedback inhibition of renin secretion
Increases sympathetic nerve activity
Stimulates secretion of ADH which will also leads to increased BP.
All factors leading to increase in BP

Question 4

1. When is AT1R activated
2. how does it function
3. Sustained activity leads to
4. what binds with greatest frequency

Answer 4

During vasoconstriction & cardiac hypertrophy & chronic CV dysfunction

2. Gq coupled GPCR. Increased IP3 & Ca = smooth muscle contraction
3. Can lead to vascular remodelling
4. AngII binds more than AngIII

Question 5

ATR2

1. stimulation effects what effects?
2. what binds with greatest frequency

Answer 5

1. Stimulation evokes effects opposite to those produced by stimulation of AT1 receptors
   - vasodilatation
   - antiproliferative
   - antithrombotic effects

Question 6

Which substrates can ACE act on

2. mechanism of action of ACE

Answer 6

Ang I, BK, Enkephalins, Substance P

2. inhibit formation of angiotensin II by preventing conversion of angiotensin I

Question 7

Consequences of ACE Inhibition

Answer 7

Fall in circulating AngII
(ang I increases & converts to Ang1-7 via ACE 2)
Reduced aldosterone secretion

Question 8

What does ANg1-7 bind and what does this result in

2. what other substrate leads to same consequences?

Answer 8

Binds Mas receptor = 
Vasodilation 
Anti-proliferation 
Anti-thrombotic 
2. Increased BK

Question 9

ACE inhibitors are used in the treatment of

Answer 9

Hypertension
decrease BP by reducing PVR
inhibit breakdown of BK
increased formation of Ang1-7 which opposes action of all

Question 10

Adverse effects of ACE inhibitors

Answer 10

Hypotension 
Renal failure 
Cough 
Angio-oedema 
effects to foetus: renal failure, renal dysplasia, hypotension, pulmonary hypoplasia, oligohydramnios