Hormonal/Lipid Mediators (Cardio) Flashcards
NSAID potency is paralled by:
Potency of prostaglandin inhibition
Arachidonic acid is a precursor for what?
biological active lipids
PUFA stands for? Comes from?
Poly-unsaturated fatty acids from our diet
How and Why would you want to store arachidonic acid?
Stored esterified in membrane phospholipids. Cause it’s POTENT once activated!
How do you RELEASE THE (arachidonic acid) KRAKKEN? (from the membrane?)
increase intracellular calcium
2 ways to metabolize arachidonic acid:
- COX1 (constitutive)- physiological PGs
2. COX2 (inducible) - gene induced by inflammatories like IL-1/TNF
COX-1 and COX-2 are expressed in which cells
ALL THE CELLS.
Features of Cyclic endoperoxides? what happens to them?
Highly unstable and converted to PGE, PGF, PGD
T/F Prostaglandins survive in the blood stream.
False. degraded by endothelial cells
PGE2 does what 5 things?
- Relaxes smooth muscle
- vasodilator
- hyperalgesic
- pyrogenic
- angiogenic
PGD2 and PGF2-alpha do what?
both bronchoconstrict
Main action of NSAIDs?
block cyclooxygenase
NSAID adverse effect?
gastric irritation/ulceration
Do NSAIDS influence cellular inflammation?
Nope. Mostly vascular.
Explain the synergy between PGE2 and BK
BK alone increases paina smidge, PGE alone only makes it red. Together they form a dynamic duo and BRING THE PAIN.
If PGE2 only acts locally, how does it get to the hypothalamus to cause fever
IL-1 travels from infection to hypothalamus, induces COX2 to produce PGE2 to turn the heat up.
PGE2 isn’t all bad, tell me 4 reasons why?
- Promotes blood flow
- promotes angiogenesis
- increases music secretion
- reduces gastric acid secretion
Is Thromboxane A2 a prostaglandin?
Nope. Missing the pentacyclin ring
What’s the half life of Prostacyclin?
3 minutes
Prostacyclin is our protector against coronary artery disease. 2 reasons why?
- reduce platelet activation
2. vasodilator
What is the half-life of Thromboxane A2?
30 seconds
What makes Thromboxane A2?
Platelets
Thromboxane A2 is prostacyclin’s evil twin brother. Two reasons why?
- increases platelet activation
2. vasoconstrictor
Why is Aspirin so special?
- Promotes prostacyclin
2. Acetylation of COX
What does Aspirin do to platelets?
irreversibly binds to them
Platelet life span is how long?
8 days
PGI2 aka….
Prostacyclin
What are Aspirin triggered lipoxins?
Lipoxins involved in inflammation resolution.
What happens if you convert linolenic acid to Eicosapentaenoic (EPA) instead of arachidonic acid?
Increase PGI3 instead of TxA3
What does Increased PGI3/TxA3 ratio mean?
lower risk of heart disease
5 Lipoxygenase does what? how is it activated? where is it found?
Inflames shit up. Activated by increased calcium via infection, allergic etc. ONLY found in inflammatory cells.
We like to target 5 lipoxygenase with drugs. Why?
It’s ONLY found in inflammatory cells so we can minimize side effects
Leukotriene B4 does shit to smooth muscle, so how does it cause inflammation?
attracts leukocytes
What does montelukast do?
blocks CysLT1R (hay fever and asthma)
Why is a local mediator only act locally?
Rapidly metabolized or ‘diluted’
6 reasons why is the Mast Cell so Mighty:
-Antigen via IgE – Complement fragments C3a/C5a – Neuropeptides – Cytokines and chemokines – Bacterial components – Physical trauma
Histamine interact with what kind of receptors?
G-Protein Coupled Receptors (H1-4)
What’s Histamine’s Triple Response?
- Reddening: vasodilation at initiating site
- Swelling: increase vascular permeability
- Flare: response through sensory fibres
What is Pruritus?
Itching
Antihistamines target which receptor?
H1
Name 2 sedative antihistamines
chlorpheniramine
promethazine
Name 2 non-sedative antihistamine drugs. Why were they withdrawn from market?
terfenadine
astemizole
Name two newer non-sedative agents?
Cetirizine
Loratidine
Name two H2 receptor antagonists. What do they treat?
Cimetidine
Ranitidine
Both treat peptic ulcers
Generally: Bradykinin is and does what?
Local peptide mediator for pain and inflam
Bradykinin degrades into Kininase I and II, Kininase II is also known as:
Angiotensin Converting Enzyme
Neural action of Bradykinin?
stimulate sensory nerve endings: Pain
Other actions of Bradykinin?
- contract uterus, airways, gut
2. epithelial secretion in airways, gut
Vascular actions of bradykinin?
Dilate arterioles and venules
Increase vascular permeability
What is icatibant?
Selective B2 receptor antagonist for Rx of hereditary angioedema (too much BK)
When the endothelium was removed from a vessel, what does Acetylcholine act like?
Vasodilator
When the endothelium was intact from a vessel, what does Acetylcholine act like?
vasoconstrictor
EDRF stand for?
endothelium-derived relaxant factor (ie. NO)
EDHF stands for? does what?
endothelium-derived hyper polarizing factor, relaxes vessels
Name the 3 isoforms of NOS
– nNOS (nerves, epithelial cells)
– iNOS (inducible- macrophages, smooth muscle)
– eNOS (endothelial cells)
What is an L-NAME?
Inhibits NOS
3 things that NOS does?
- inhibit platelet adhesion and aggregation
- Neurotransmitter
- Wasodilates in response to shear forces