Signaling Lipids Flashcards
Signaling lipids are responsible for regulating what important process?
Inflammatory response
What is AA and why is it important?
AA or arachidonic acid is a precursor to numerous bioactive lipids
What enzymes are responsible for converting AA to prostaglandins?
Cox-1 and Cox-2 convert AA into prostaglandin H2 (PGH2)
Cox-1
Expressed in most tissues
Cox-2
Expression of this enzyme increases during inflammation
What is prostaglandin E2 (PGE2)
- Synthesized by the enzyme prostaglandin E synthase (PGES-1) from PGH2
- Plays multiple roles during inflammation / sickness including:
- Pain
- Swelling
- Fever
- Appetite suppression
How does PGE2 exert fever symptoms?
- PGE2 activates 4 distinct receptors (EP1-EP4)
- EP1, EP2, EP4 = activators
- EP3 = inhibitor
What are nociceptors?
Specialized nerves that transmit panful stimuli from the site of inflammation to the spinal cord
How does inflammation affect nociceptors?
Inflammation increases nociceptor activity and enhances pain
How does PGE2 increase nociceptor activity?
PGE2 activates EP2 and EP4 receptors
How can you stop fever symptoms?
- Cox inhibitors
- Prostaglandins are synthesized by Cox-1 and Cox-2 during inflammation (prostaglandins induce fever symptoms)
- Inhibition of Cox reduces pain, inflammation, and fever
What are some examples of Cox inhibitors?
- Aspirin
- Ibuprofen
What are some effects of Cox inhibitors?
- Gastrointestinal ulcerations
Cox-1 protects gastric mucosa from gastric acid
What has been used in place of Cox inhibitors in order to suppress fever symptoms?
- Therapeutic targeting of PGES-1 (enzyme that produces PGE2)
- Inhibition of PGES-1 reduces levels of PGE2 without affecting the synthesis of prostacyclins
What are leukotrienes
Bioactive lipids synthesized from AA
