Cardiovascular I Flashcards
CNS Neurotransmitters
Epi, NE, dopa, serotonin, GABA, ACh
Agonists
Natural Catecholamines
Epi, NE, dopa
Agonists
Synthetic Catecholamines
Isoproterenol & dobutamine
α
Receptor Potency
NE > epi > Isoproterenol
β
Receptor Potency
Isoproterenol > epi > NE
α1 Receptors Location
Post-synaptic
Locations: CV (heart), vasculature, glands, & gut
α1 Receptors MOA
Activation causes vasoconstriction & GI tract relaxation
Eye - iris (radial muscle) contraction → pupil dilation (mydriasis)
α2 Receptors Location
Pre-synaptic AND post-synaptic
α2 Pre-Synaptic
1° location pre-synaptic
Location: CV (coronaries), peripheral vascular smooth muscle, & brain
Activation causes NE release inhibition & inhibits sympathetic outflow → vasodilation
↓BP ↓HR → inhibit CNS activity
α2 Post-Synaptic
Location: CNS & coronaries
Activation causes constriction, sedation, & analgesia
β1 Location
ONE HEART
Cardiac muscle (myocardium), SA node, ventricular conduction system, coronaries, & kidney
β1 MOA
Activation causes ↑inotropy, chronotropy, myocardial conduction velocity, coronary relaxation, & renin release
β2 Location
TWO LUNGS
Vascular, bronchial & uterine smooth muscle, skin smooth muscle, myocardium, coronaries, kidneys, & GI tract
β2 MOA
Vasodilation, bronchodilation, uterine relaxation, gluconeogenesis (↑glucose), glycogenolysis (breaks down glycogen → glucose), insulin release, K+ uptake (cellular)
Ephedrine MOA
Direct & indirect (NT release) α/β
→ vasoconstriction ↑HR ↑inotropy
Phenylephrine (Neo-synephrine) MOA
Direct α vasoconstriction → reflex bradycardia
What determines blood pressure?
BP = CO x SVR CO = (HR x SV)
What factors influence SV?
Contractility
Preload - venous tone & intravascular volume
How do β blockers & Ca2+ channel blockers ↓BP?
↓HR & contractility
BP = HR x SV x SVR
What drugs impact venous tone & therefore preload?
α1 agonists
α blockers
Angiotensin converting enzyme inhibitors ACEi -pril
Angiotensin II receptor blockers ARBs -sartan
Direct vasodilator - Nitroprusside
How do diuretics, ACEi, & ARBs influence BP?
Renin-angiotensin-aldosterone
Na+ & H2O retention/excretion → PRELOAD
What drugs directly innervate SVR?
α1 antagonists
α2 agonists
What drugs influence circulating regulators that determine SVR?
α1 antagonists
α1 agonists
ACEi & ARBs
What drugs influence local SVR regulators? How?
- Endothelin antagonists
- Nitroprusside
- ACEi
- ARBs