Eicosanoid metabolism Flashcards
1
Q
Aspirin
A
- Inhibits TXA2
2
Q
NSAID
A
- Aspirin inhibits both COX-1 & COX-2
- covalent acetylation of SER530
- Celecoxib inhibits COX-2
- Rx: arthritis & menstrual cramps
- Irreversible inhibition
3
Q
Asthma Rx
A
Inhibition of leukotriene synthesis
- Corticosteroid inhibition of PLA2
- 5’Lipoxygenase inhibition, eg. Benoxaprofen, Zileuton
Inhibition Leukotriene Receptor
- Cysteinyl-Leukotriene Receptor antagonists
4
Q
Corticosteroids
A
- anti-inflammtory preventing bronchoconstriction
- Genetic level MOA
- Induces release of phosphorylated formm of Annexin-1 protein involved in inhibiting PLA2
5
Q
Leukotriene Receptor antagonists
A
- Cysteinyl-Leukotriene (CysLT) receptors have imp. actions in cardio & resp systems
- CysLT receptor antagonists prevents bronchoconstriction
- Zafirlukast
- Montelukast
- Lukast
- Less effective than Salbutamol, a ß-AR agonist
- Zileutin inhibits LOX-5 reducing formation of LTB4 & CysLT
6
Q
Zileuton
A
- LOX-5 blocker
- reduces formation of LTB4 & CysLT (LTC4, LTD4 & LTE4)
- Leukocytes
7
Q
TXA2
A
- produced primarily by platelets
- promotes platelet aggregation
- decreases formation of cAMP
- vasoconstriction
- bronchoconstriction
- mobilizes intracellular Ca2+
- contraction of smooth muscle
- lymphocyte proliferation
8
Q
PGE2
A
- produced by most tissues especially the kidney
- vasodilation
- relaxes smooth muscle
- used to induce labour
9
Q
PGF2alpha
A
- produced by most tissues
- vasoconstriction
- contraction of smooth muscle
- stimulates uterine contractions
10
Q
PGI2
A
- produced primarily by endothelium of vessels
- vasodilation
- inhibits platelet aggregation
- increases formation of cAMP
11
Q
EPA is a precursor for?
A
- series-3 PG which includes PGE3
12
Q
Arachidonic acid is a precursor for?
A
- Series-2 eicosanoids including PGE2, PGI2 & TXA2
*
13
Q
SC-558
A
- Strong inhibitor of COX-2
- Weak inhibitor of COX-1
14
Q
Cysteinyl-leukotrenes
A
- LTC4
- LTD4
- LTE4
- more potent than histamine in stimulating smooth muscle contraction of bronchi & intestines
*
15
Q
Slow-Reacting Substance of Anaphylaxis (SRS-A)
A
- mixture of leukotrienes LTC4, LTD4 & LTE4