Eicosanoids

Question 1

What does ‘eicosa’ mean?

Answer 1

Twenty

Question 2

What are two classical eicosanoids?

Answer 2

Prostanoids

Leukotrienes

Question 3

What are 4 non-classical eicosanoids?

Answer 3

Lipoxins
Resolvins
Isoprostanes
Endocannabinoids

Question 4

Under basal conditions, is synthesis or prostaglandins high or low?

Answer 4

Low

Question 5

Name 5 prostanoid receptors

Answer 5

TxA2
PGD2
PGE2
PGI2
PGF2a

Question 6

Where are TxA2 receptors found?

Answer 6

Platelets, VSMCs, macrophages, kidney

Question 7

Where are PGD2 receptors found?

Answer 7

Mast cells, brain, airways

Question 8

Where are PGE2 receptors found?

Answer 8

Brain, kidneys, VSMCs, platelets

Question 9

Where are PGI2 receptors found?

Answer 9

Endothelium, VSMCs, platelets, kidney, brain

Question 10

Where are PGF2a receptors found?

Answer 10

Uterus, airways, VSMCs, eyes

Question 11

Prostaglandins act via what on target cells?

Answer 11

GPCRs

Question 12

How many PGE2 receptors are there?

Answer 12

4

Question 13

PGI2 receptor is Gs Gi or Gq linked?

Answer 13

Gs

Question 14

Thromboxane receptor is Gs Gi or Gq linked?

Answer 14

Gq

Question 15

What are the 4 functions of PGs?

Answer 15

Initiation of labour.
Inhibition of gastric secretion.
Inhibition of platelet aggregation and vasodilation.
Platelet aggregation and vasoconstriction.

Question 16

What is PGI2 from endothelium responsible for?

Answer 16

Inhibition of platelet aggregation and vasodilation

Question 17

What is TxA2 from platelets responsible for?

Answer 17

Platelet aggregation and vasoconstriction

Question 18

How is EP2 potentially pro-inflammatory?

Answer 18

Gs/AC mediated elevation of cAMP in smooth muscle vasodilates

Question 19

How is EP2 potentially anti-inflammatory?

Answer 19

Gs/AC mediated elevation of cAMP in leukocytes inhibits function

Question 20

What does EP3 receptor do?

Answer 20

Activates leukocytes and mast cells.

Enhances oedema formation.

Question 21

What do prostaglandins do to peripheral C-fibres?

Answer 21

sensitise them which increases pain response to other agents.

Question 22

EP1 receptor knock out mice have increased or decreased inflammatory pain responses?

Answer 22

Decreased

Question 23

Cerebroventricular injection of PGE2 leads to what?

Answer 23

Fever

Question 24

What is Cox1?

Answer 24

Constitutive housekeeping enzyme

Question 25

The products of COX1 are important in what?

Answer 25

Normal function of the stomach, intestine, kidney and platelets

Question 26

What is COX2?

Answer 26

An enzyme induced in inflammation

Question 27

What is COX3?

Answer 27

Splice variant of COX1 gene expressed in CNS

Question 28

What is COX2 induced by?

Answer 28

TNFa

IL-1

Question 29

Where are COX1 and COX 2 found?

Answer 29

Inner membrane of endoplasmic reticulum

Question 30

What does aspirin do?

Answer 30

Acetylates serine residues in COX 1 and 2

Question 31

What does COX2 specificity mean?

Answer 31

Inhibition of COX2 but not COX1 across the entire therapeutic dose range.

Question 32

What are the side effects of aspirin like drugs?

Answer 32

Gastric irritation and bleeding, renal toxicity, bleeding

Question 33

Why does aspirin cause the S/Es it does?

Answer 33

Due to blocking the ‘housekeeping’ COX1 and thus reducing the cytoprotective effects of PGs.

Question 34

Platelet COX1 inhibition is beneficial in what?

Answer 34

Thrombosis

Question 35

What are the 4 actions of leukotrienes?

Answer 35

Bronchoconstriction
Oedema
Chemotaxis
Present in inflammation

Question 36

Glucocorticoids inhibit what?

Answer 36

PLA2

Question 37

Zileuton inhibits what?

Answer 37

5-lipoxygenase

Question 38

Zafirlukast and montelukast inhibits what?

Answer 38

LTC4 and LTD4

Question 39

NSAIDs inhibit what?

Answer 39

COX

Question 40

Glucocorticoids essentially inhibit what?

Answer 40

COX-2 synthesis