Endothelial Function

Question 1

Why is smooth muscle growing in blood vessels a bad sign?

Answer 1

Can lead to blockage

Smooth muscle can change from contractile > synthetic

Question 2

What are relaxing agents?

Answer 2

NO

PG’s (Prostacyclin)

Question 3

What are the contracting agents?

Answer 3

Endothelin I
Angiotensin II (ACE turns angiotensin 1 > 2 = strong vasoconstriction)

Question 4

How is Prostacyclin derived and what does it do?

Answer 4

• derived from AA by PGHS
• inhibits platelet aggregation via cAMP
• relaxes smooth muscle via cAMP
• inhibits prolif. of vasc. smooth muscle

Question 5

How is NO derived and what does it do?

Answer 5

• produced by endothelium
• inhibits platelet aggregation via cGMP
• relaxes smooth muscle via cGMP
• inhibits prolif. of vasc. smooth muscle
• locally acting
• implicated in pathological states (superoxides from oxidative stress can inactivate it)

Question 6

What does Endothelin I do?

Answer 6

• no effect on platelets
• most potent vasoconstrictor
• stimulates prolif. vasc. smooth muscle
• implicated in pathological states (hypertension)

Question 7

What does nitric oxide synthase (NOS) do?

Answer 7

Synthesises NO from L-arginine

Question 8

What are the 3 types of NOS?

Answer 8

1) ec NOS
- Endothelial isoform
- Ca dependent
- Produces NO in response to ACh + shear stress
2) n NOS
- Neuronal isoform
- Ca dependent
3) i NOS
- Ca independent
- Expression induced by exposure to inflam.

Question 9

What effect does oestrogen have on vascular smooth muscle relaxation?

Answer 9

Premenopausal oestrogen = cardioprotective > stimulates endothelial cells to release NO
Post menopause = increased risk HD

Question 10

What are the uses of NO?

Answer 10

• kills bacteria in macropages
• communication between neurons (NANC = thought uses as NT)
• egg fertilisation
• pulmonary hypertension (dilates BV in lungs)

Question 11

How does NO work?

Answer 11

Binds to soluble guanylate cyclase = increased cGMP/PKG = reduces IC Ca = smooth muscle relaxation

Question 12

Describe atherosclerotic classification

Answer 12

• eccentric
• lumen deforming
• fibrous intimal cap
• fibrous elastinolysis
• vessel stiffening

Question 13

Describe medial calcification

Answer 13

• concentric
• medial fibrosis + elastinolysis
• adventitial inflammation
• vessel stiffening