drugs and the vasculature Flashcards
what does the sympathetic nerve have along its length?
- varicosities
- primarily release NA to stimulate vasoconstriction
name some VSM mediators that can inc. Ca and stimulate VSM contraction? What receptors do they bind to?
- AngII –> AT1r
- PGG2, PGH2 –> T-prostanoid receptor
- ET1 –> ETA/B
name some endothelial cell agonists that can stimulate a relaxation from an inc. in Ca
- NO
- CNP (C type naturietic peptide)
- PGI2
- EDHF (endothelial hyperpolarising factor)
what is BP mediated by?
CO and TPR
BP = CO x TPR
which vessels contribute the most to BP regulation?
- arterioles contribute the greatest to BP regulation
- these vessels have vascular tone
- so always display partial state of constriction
in terms of vascular tone, what do hypertensive patients have?
have a raised base vascular tone
= more TPR
= more BP
define hypertension
> 140/90mmHg
describe the treatment overview
step 1: single therapy (U55 - ACEi or ARB, O55/ Afro-carribbean - CCB or thiazide diuretic)
Step 2: Dual therapy (ACEi and CCB or ACEi and thiazide diuretic)
Step 3: Triple therapy (ACEi, CCB, thiazide diuretic)
Step 4: Symptomatic relief (low dose spironolactone, beta/alpha blockade)
name an ACEi
Enalapril
often have -ipril endings
what is RAS stimulated by?
- low renal Na reabsorption
- low renal perfusion pressure
- High SNS activation
what do ACEi do?
- dec. AngII production
- inc. bradykinin
what are some uses of ACEi?
- hypertension
- HF
- Post MI
- diabetic nephropathy
- progressive renal insufficiency
- high CVS disease risk patients
how are ACEi effective in hypertension treatment?
- reduce TPR (more bradykinin and less AngII –> reduces TPR via less AT1R-mediated vasoconstriction and more bradykinin vasodilation)
- sodium retention (less Na retention in kidneys via blocked actions of AngII and less aldosterone secretion)
- thirst drive (less SNS activation of thirst in brain via AT1R)
how are ACEi used to treat HF?
- reduced TPR (less vasoconstriction via AT1R in vasculature so less afterload = dec. ionotropic effects)
- reduce preload (venodilation means less preload)
what do ARBs (Angiotensin Receptor Blockers) do?
e.g. Losartan
prevent binding of AngII to AT1 receptors
