4.3 - Eicosanoids Flashcards
Eicosanoids
- Biosynthesis
* Effects
Biosynthesis
Sources
Sources
• Phospholipids (major)
• Phosphatidyl inositol (alternative)
⬇️⬇️⬇️
Arachidonic Acid
Phospholipids ➡️ Arachidonic Acid
Phospholipase A2
Phosphatidyl inositol ➡️ Arachidonic Acid
Phospholipase C
Arachidonic Acid ⬇️ – Prostaglandins – Thronboxanes – Prostacyclin (PGI2)
Cycolooxygenase (COX)
Arachidonic Acid
⬇️
Leukotrienes
5-Lipoxygenase (LOX)
– 5, 8, 11, 14-eicosatetraenoic acid
– 20C; 4 double bond
Arachidonic Acid
Cyclooxygenase
- Prostaglandins
- Thromboxanes
- Prostacyclin (PGI2)
– Cytoprotection
– Vasodilation
– Pain & Inflammation
Prostaglandins
– Platelet aggregation
– Vasoconstriction
Thromboxanes
5-Lipooxygenase
Leukotrienes
Leukotrienes
- LTB4
* LTC4/ LTD4
– Chemotactic factor
– Induces the movement of immune cells
LTB4
– SRSAs
– Slow-reacting substance of Anaphylaxis
LTC4/ LTD4
Effects
- Blood vessels
- Bronchi
- GIT
- Platelets
- Uterus
- Reduction of intraocular pressure
Blood vessels
- Vasodilation
* Vasoconstriction
Vasodilation
- PGI2 (Prostacyclin)
* PGE series
Vasoconstriction
- TXA2
* PGF2a
Bronchi
- Bronchodilation
* Bronchoconstriction
Bronchodilation
- PGI2
* PGE series
Bronchoconstriction
- LTC4
* LTD4
GIT
Cytoprotection
– PGE1
Platelets
- Platelet aggregation
* Inhibition of platelet aggregation