Sympathetic Activation & Inhibition Flashcards
Adrenergic receptors
alpha1
alpha2
beta1
beta2
Alpha1 stimulation
Vascular smooth muscle contraction
- increase peripheral resistance
- increase BP
- Mydriasis
- increase bladder sphincter muscle contraction
Where are alpha2 receptors located?
- beta cells (pancreas)
- Certain smooth muscle cells
- Presynaptic nerve
Alpha2 stimulation
inhibit NE release (negative feedback mechanism)
Beta1 stimulation
- Increase HR (Tachycardia)
- Increase lipolysis
- Increase myocardial contractility
- Increase release of renin
(HEART)
Beta2 stimulation
- Vasodilation
- Slight decreased peripheral resistance
- Bronchodilation
- Increased lipolysis
- Increased insulin release
- Decreased uterine tone
- Response to drop in BP 2/2 vasodilation, HR will increase
Skeletal muscles have what type of receptors?
alpha1
beta2
Heart has what type of receptors?
beta1
Lungs have what type of receptors?
beta2
Direct sympathomimetics: mechanism?
Bind adrenergic receptors, without interacting with the presynaptic neuron
Direct sympathomimetics:
examples?
Epinephrine Norepinephrine Isoproterenol Dopamine Dobutamine Phenylephrine Albuterol / Levalbuteral / Salmeterol Terbutaline Clonidine
Epinephrine: which receptors?
alpha1
alpha2
beta1
beta2
Epinephrine: uses?
Anaphylaxis
Severe croup
Hypotension
Norepinephrine: which receptors?
alpha1 (Strong)
alpha2 (Strong)
beta1
Norephinephrine: use?
Hypotension
Septic shock
Cardiac shock
Isoproterenol: receptors?
beta1
beta2
not used clinical anymore
Dopamine: receptors?
Low doses - dopamine receptors
Medium doses - beta1 & beta2
High doses = alpha1 & alpha2
Used in shock, but studies showed that it actually did not help in renal perfusion…
Dobutamine: receptors?
beta1 (HEART)