Arachidonic Acid Derivatives (4 star!!!)

Question 1

What cell membrane component is cleaved to form arachidonic acid? Enzyme?

Answer 1

Phosphatidylinositol–> Phospholipase A2 catalyzes

Question 2

What enzyme cleaves arachidonic acid to make leukotrienes? What product is formed?

Answer 2

Lipoxygenase–> Hydroperoxides (precursor to all LTs)

Question 3

What drug inhibits lipoxygenase? Purpose?

Answer 3

Zileuton–> blocks leukotriene synthesis to prevent bronchoconstriction

Question 4

What are the two functions of leukotrienes? Which ones responsible for each?

Answer 4

1. Neutrophil chemotoxis (LTB4)

2. Increased bronchial tone (LTC4, LTD4)

Question 5

What two drugs are leukotriene receptor antagonists?

Answer 5

1. Zafirlukast

2. Montelukast (approved for children)

Question 6

What molecule is the precursor for prostacyclins, prostaglandins, and thromboxane? What enzyme catalyzes its creation from arachidonic acid?

Answer 6

Endoperoxides–> Cyclooxygenase catalyzes (COX-1, COX-2)

Question 7

4 functions of Prostacyclin (PGI2)

Answer 7

1. decreased platelet aggregation (platelet-gathering inh.)
2. decreased vascular tone
3. decreased bronchial tone
4. decreased uterine tone
   * DECREASES EVERYTHING

Question 8

4 functions of prostaglandins (PGE2, PGF2 alpha)

Answer 8

1. increased uterine tone
2. decreased vascular tone
3. decreased bronchial tone
4. increased gastric mucous production (protects gastric epithelium)

Question 9

3 functions of thromboxane (TXA2)

Answer 9

1. increased platelet aggregation
2. increased vascular tone
3. increased bronchial tone

*prostacyclin and thromboxane have opposite effecs (but prostacyclin affects uterine tone, thromboxane doesnt ((“P” = messes with uterus, aka Pussy))

Question 10

What enzyme do corticosteroids block?

Answer 10

Phospholipase A2

Question 11

What are 4 COX inhibitors?

Answer 11

1. NSAIDS
2. Aspirin (binds irreversibly)
3. Acetaminophen
4. celecoxib (COX-2 specific)

Question 12

What is different about acetaminophen from most COX inh.?

Answer 12

Inactivated peripherally, so no anti-inflammatory effects and no effects on platelet function

Question 13

Increased bronchial tone (2)

Answer 13

1. leukotrienes (LTC4, LTD4)

2. thromboxane (TXA2)

Question 14

Decreased bronchial tone (2)

Answer 14

1. Prostacyclin (PGI2)

2. Prostaglandin

Question 15

Increased platelet aggregation (1)

Answer 15

Thromboxane

Question 16

Decreased platelet aggregation (1)

Answer 16

Prostacyclin

Question 17

Increased uterine tone (1)

Answer 17

Prostaglandin

Question 18

Decreased uterine tone (1)

Answer 18

Prostacyclin

Question 19

Increased vascular tone (1)

Answer 19

Thromboxane

Question 20

Decreased vascular tone (2)

Answer 20

1. Prostaglandins

2. Prostacyclins