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11 Cards in this Set
- Front
- Back
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Mediators of vascular changes in Inflammation:
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vasoactive amines -> histamine and seratonin
vasoactive peptides -> angiotensin and bradykinin vasoactive lipids -> corticosteriods and leukotrienes |
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Eicosanoids - def.
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Prostaglandins and related compounds are collectively known as Eicosanoids
They are dervied from arachidonic acid (20-C polyunsaturated fatty acid) |
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Eicosanoid metabolism
Two pathways |
Cyclooxygenase:
Prostaglandins + prostacyclines + thromboxanes from PGH2, from arachidonic acid via PGH2 synthase Lipoxygenase: LTs from arachidonic acid |
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Kinins
Synthesis? Role? |
Bradykinin is synthesized from kininogen via kallikrein which is activated upon tissue injury due to exposure of Hageman factor
Effects: Vasodilation and ++vascular permeability, PAIN, spasm of smooth muscles (uterus,bronchus,gut) It is cleaved by ACE (kininase II) which also cleave angiotensin I to activate angiotensin II --> inactivates a vasodilator and activates a vasoconstrictor Two receptors B1,B2 |
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Angiotensin in the regulation of BP
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1. Renin-angiotensin system (kidney & adrenal cortex) --> days-weeks
2. Angiotensin acts on baroreceptors in aorta and carotids --> mins |
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Renin-angiotensin system
triggers? |
Renin release is stimulated by:
1. ↓ stretch afferent renal arteriole 2. ↓ Na in distal tubule 3. beta 1 sym. stim of JGC (where renin is synth) Angiotensinogen (angiotensi precursor) increase due to: Corticosteriods, estrogens, thyroid hormone, angiotensin II (think of your perio recall pt Alina, she's on antihypertensives, post menopausal and her TH is low) |
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Renin-angiotensin system
Outcome? |
Angiotensin II is final product which:
- ↑ E,NE from adrenal medulla - ↑ release, ↓ reuptake of NE from sym neurons - ↑ release of vasopressin and ACTH - ↑ aldosterone => results in +ve inotropic effect on heart and dipsogenic response and consequently blood volume (water drinking), growth of cardiac and smooth muscles, Na retnetion, K excretion, increase BP |
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Renin angiotensin system
Points of intervention? |
- Renin release and activity
- ACE inhibitors - Angiotensin II receptors (RT1/2; 1 more potent) |
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Renin interventions
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Beta 1 block: propronolol, metaprolol
alpha 2 agonist: clonidine, methyldopa |
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ACE inhibitors
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captopril: used in hypertension, heart failure, diabetic nephropathy
other ACEis end with -pril |
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Angiotensin II (AT II) block
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Saralsin - peptide analog of AT II; antagonist at high AT II, parital agonist at low AT II
Non-pep antagonists (-artan): e.g Valsortan, Losartan(cozaar) |
