Chapter 35: Eicosanoids Flashcards
What enzyme do glucocorticoids target and what does this do?
Phospholipase A2 - prevents formation of arachidonic acid
also prevent transcription/translation of COX2
How does aspirin work?
Inhibits COX - the enzyme that converts arachidonic acid into PBG2 in the formation of prostaglandins, prostacyclin, and thromboxane
In humans, prostaglandins are derived primarily from __?
arachidonic acid
The signal that leads to an increased intracellular calcium level is initiated by what enzyme?
phospholipase C
PGD2 function
smooth muscle contraction
inhibits platelet aggregation
PGE2 function
vasodilation
hyperalgesia
immunomodulation
PGF2a function
smooth muscle contraction
abortion
bronchoconstriction
PGI2 function
produced by vascular endothelial cells
inhibits platelet aggregation
vasodilation
TXA2 function
produced by platelets platelet aggregation vasoconstriction bronchoconstriction lymphocyte proliferation
COX pathways leads to formation of …?
prostaglandins, prostacyclin, and thromboxane
How do cold water fish help prevent platelet aggregation craps?
Containing EPA and DHA fatty acids = more formation of TXA3 over TXA2 ….
TXA3 is a worse stimulator of platelet aggregation
How does aspirin help to prevent an MI?
Blocks production of TXA2 from arachidonic acid!
COX1 vs COX2
COX1: platelet aggregation and stomach cytoprotection
COX2: hyperalgesia and inflammation
LTC4 and LTD4 fx
increase bronchoconstriction
increase vascular permeability
IFN-y
LTE4 fx
decrease coronary flow and contractility (mast cells, basophils, eosinophils)
LTB4 function (and what inhibits it?)
increases vascular permeability t cell proliferation leukocyte aggregation INF-y IL1 & 2 Neutrophils
- inhibited by adenosine
Lipoxin A4 (LXA4) function
induce chemotaxis
stimulate superoxide production in leukocytes
What finding in the urine can be used as a marker for oxidative stress from a disorder? (like Parkinson, Alzheimer, Lou Gehrig)
isoprotanes
What is the big enzyme in isoprostane synthesis?
NONE! non enzymatic stupid
endocannibinoids bind to what receptors?
CB1 and CB2 (analgesia affects on nervous system?)
What can be administered to keep a PDA open?
PGE1
Which prostaglandins can be used to inhibit gastric secretion?
PGE1 and PGE2
What can be used to induce labor (or abortion if early!)
PGE2 or PGF2a
Inhaled ____ can help with asthma.
corticosteroids
COX 2 selective inhibitors - contraindication?
do not use for pts with ischemic heart disease or stroke hx
Vioxx
COX2 inhibitor withdrawn from market
When does COX1 hang around? COX 2?
COX 1 is always hanging around (overprotective mom)
COX2 hangs out in high levels of inflamed tissue because its regulated by cytokines etc (spiderman - comes when help is needed)
