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24 Cards in this Set
- Front
- Back
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What are lipids?
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Fats, oils, waxes, triglycerides, sterols
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What are autacoids? What are eicosonoids?
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Substances that are rapidly synthesized in response to stimuli, act quickly at an immediate locality, nad are degraded quickly.
Eicosanoids are arachidonic acid derived autacoids |
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How many carbons do eicosenoids have? What response do they help generate?
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They have 20 carbons. They hel generate the inflammatory response
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What is the difference between arachidonic acid and eicosapentaenoic acid. What structural difference causes this difference?
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AA is inflammatory, whereas eicosapentaenoic acid is anti-inflammatory. This difference arises from eicosapentaenoic acid's extra double bond
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What does phospholipase A2 do?
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It generates arachidonic acid from membrane phospholipids
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Arachidonic acid is the precursor to the eicosanoids. What are two examples of classes of eicosanoids?
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Two examples of eicosanoids are leukotriene and prostaglandin
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The cyclooxygenase enzymatic pathway produces what three eicasonoids from AA?
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It produces prostaglandins (including thromboxane, and prostacyclin)
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What causes different eicosanoids to be produced in different tissues?
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The different enzymes local to that tissue (prostaglandin synthase, for example)
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What are Cox 1 and 2? When is Cox-1 expressed? What functions is it associated with?
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Cox 1 and 2 are cyclooxygenases, which produce prostaglandins from AA. Cox-1 is always expressed. It is believed to produce pro-inflammatory prostaglandins as well as homeostasis. It is also involved with intestinal mucosa proliferation, hence NSAID overdose is involved with gastric ulcers
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Is Cox-2 always expressed or inducible?
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Cox 2 is inducible. It is believed to be exclusively involved in the pro-inflammatory response, without the homeostatic component. (this is why Cox-2 inhibitors may be more desirable than general Cox inhibitors). It is helps produce prostaglandins involved in inflammation, pain, fever, and ovulation
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Eicasonoids have various inflammatory functions. What is PGD2 involved with? PGE2? TXA2? PGI?
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PGD2 - hypersensitivty reactions
PGE2 - inflammation, fever pain, vasular permeability TXA2 (thromboxane) - platelet aggregation and vasoconstrictor PGI2 (prostacyclin) - opposite of thromboxane, anticoagulant and vasodilator |
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What protein receptor mediates the response to prostaglandins?
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A G protein coupled receptor
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Describe the pathway of Cox 2 activation.
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Ligand binds a receptor, which activates a receptor. This causes upregulation of Cox2. More Cox 2 is present, so when phospholipase 2 forms AA from phospholipids, it can go to Cox2. This converts it into PGH2, an important intermediate in prostaglandin synthesis
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What sort of functions do eicasonoids have in infammation?
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Vasoconstriction, edema, chemotaxis, increased vascular permeability, pain,
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What enzymes convert AA into leukotrienes? What is the main function of leukotrienes? From what cells are they released?
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Lipoxygenase converts AA into leukotrienes. Leukotrienes are mainly chemoattractants for leukocytes, but also have some vascular effects, including vasocontstriction They are released from mast cells, eosinophils and basopihils.
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What is the relationship between leukotrienes and asthma? How do they compare to histamine?
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The leukotrienes LTC4, LTD4, LTE4, are the main actors in asthma, by causing bronchoconstriction and bronchospasm - they are more bronchoconstricting than histamine.
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What are the two mechanisms to block leukotrienes with drugs? What are drugs inolved in these, and what do they treat?
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Leukotrienes can be blocked either by inhibition of leukotriene production or antagonizing leukotriene receptors (GCPRs). Singulair is a leukotriene receptor antagonist. It treats asthma
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Which leukotriene is involved with chemotaxis?
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LTB4
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What is an example of an NSAID? What do NSAIDs do? What is the difference between Cox1 and Cox2? Why would Cox-
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Aspirin is an NSAID. NSAIDs inhibit both COX-1 and COX-2, inhibiting prostaglandin synthesis. Cox1 is everywhere, and is involved in "housekeeping" functions, including GI tract homeostasis. Cox2 is inducible, and may be exclusively pro-inflammatory
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Celebrex and Vioxx are what types of drugs?
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They are Cox-2 inhibitors - so they can achieve the anti-inflammatory effect without inhibiting Cox-2, which has housekeeping roles, especially in the gut.
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What is the role between colon cancer and Cox2? How does relate to treatment? What were the problems with this?
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Cox2 is higher in colon cancer patients. Vioxx (a Cox-2 inhibitor) was shown to reduce polyps, thus treating colon cancer. However, it was associated with increased cardiovascular events, since Cox-2 inhibition is pro-thrombotic.
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Describe Cox-2 vs NSAIDs affects on clotting. Which eicosanoids are affected specifically?
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Cox-2 is pro-thrombotic, whereas NSAIDs (both Cox-1 and Cox-2 inhibitor) are anti-thrombotic. This is because the pro-thrombotic thromboxane (TxA2) in platelets is made through Cox1. Prostacyclin (PGI2) in endothelial cells is made by both Cox1 and Cox2.
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What enzyme converts AA into leukotrienes?
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Lipoxygenase
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What is a general name for COX-2 inhibitors?
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Coxibs
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