10 - Adrenergics Flashcards
What are the effects of alpha 1 receptor activation in the:
- Eyes
- Arteries
- Veins
- GU Smooth muscle male
5: Vas deferens
- Eyes: constriction of radial muscle of the iris
- Arteries: constriction
- Veins: constriction
- GU smooth muscle male: constriction
- Vas Deferens: ejaculation
What are the effects of alpha 2 receptor activation in the:
- Pre-synaptic nerve terminals
- CNS
Presynaptic nerve terminals: inhibition of transmitter release
CNS: Inhibition of sympathetic outflow to blood vessels
What are the effects of B1 receptor activation in the heart and kidney?
Heart: increased rate and forces of contraction and increased AV nodal conduciton velocity
Kidney: renin release
What are the effects of B2 receptor activation in the:
- Arteries
- Bronchi:
- Skeletal muscle
- liver
- Arteries: dilation
- Bronchi: dilation
- Glycogenolysis
- Glycogenolysis and gluconeogenesis
What is the effect of domamine1 receptor in the arterteris of the kidney and mesentery?
Dilation
Sympathomimetics mimic the effects of ______ activation?
sympathetic
What type of smooth muscles and glands do sympathomimetics have excitatory actions on? What other excitatory action does it have?
Blood vessels, radial muscle, salivary glands, sweat glands
Cardiac excitatory actions
What type of smooth muscle is inhibited by sympathomimetics?
Wall of the gut, bronchial tree, blood vessels supplying skeletal muscle.
What are the metabolic actions of sympathomimetics?
Glycogenolysis (liver and skeletal muscle), gluconeogenesis (liver), and liberation of free fatty acids from adipocytes.
What are the endocrine actions of sympathomimetics?
Decrease release of insulin and increase release of renin.
What actions do sympathomimetics have in the CNS?
Respiratory stimulation, increase wakefulness, psychomotor activity, reduction in appetite.
What are the three types of adrenergic agonists?
Direct acting, mixed acting, and indirect acting.
What are the two types of direct acting adrenergic agonists?
Selective and non-selective
What are the types of indirect-acting adrenergic agonists?
Releasing agents, uptake inhibitors, MOA inhibitors, COMT inhibitors.
What are the catecholamines? What metabolizes them? What are some important properties?
Norepinephrine, epinephrine, dopamine.
Rapidly metabolized by MAO and COMT and not effective by oral administration
Short T1/2 and must be given parenterally
What receptors are selective for epinephrine?
a1, a2, B1, and B2.
What are the cardiovascular effects of epi? What are the respiratory effects? Metabolic effects?
CV: potent vasopressor (a2) but can dilate some vascular beds (B2), cardiostimulatory (B1)
Resp: bronchodilation (B2)
Metabolic: increases blood glucose and fatty acids
What are the therapeutic uses of epinephrine?
Hypersensitivity reaction; anaphylaxis.
Increases duration of action of local anesthetics,
Bradyarrhythmias (slow HR)
Mydriatic (dilation) , decreases hemorrhage and conjunctival congestion.
What is the result of low epinephrine concentrations in blood vessels of skeletal muscles? High?
Low concentration: B2 dilation
High concentration: a1 constriction
What is the receptor selectivity of norepinephrine?
a1, a2, B1
What are the CV effects of norepi?
(a1 mainly)
- Increases pulm. vascular resistance
- Increases mean BP
- can cause reflex bradycardia
What are the therapeutic uses of norepinephrine?
Vasoconstrictor under certain intensive care situations such as shock and hypotension during reduced sympathetic tone.
What is the effect of a low dose of dopamine? What receptor is involved?
“renal dose” dilation of renal and mesenteric arteries
causes a decrease in peripheral vascular resistance (D1 receptor)
What is the effect of an intermediate dose of dopamine? What receptor is involved?
“cardiac dose”
Increases HR, contractive force, cardiac output
D1 + B1 receptor
What is the effect of a high dose of dopamine? what receptor is involved?
“pressor dose”
Vasoconstriction and increased peripheral vascular resistance
D1 + B1 + a1
What is the absorption, fate, and excretion of dopamine? What is the therapeutic use?
Similar to epinephrine; administered IV and dose is titrated to achieve desired effect.
Therapeutic use: severe decompensated heart failure, shock (cardiogenic or septic).
What is the receptor selectivity of isoproterenol?
B1 and B2
What are the CV and respiratory effects of isoproterenol?
CV: decrease PVR, increase HR, contractile force, CO, decreased mean BP.
Rep: bronchodilation
what is the absorption and fate of isoproterenol? What is the therapeutic use?
Metabolized by COMT and has a brief duration of action.
Emergency use to stimulate heart rate during bradycardia or heart block.
What is the overall effect of Dobutamine?
It’s a racemic mixture that functions as a B1 agonist.
What are the CV effects of dobutamine?
Increased HR, contractility, and CO.
Minimal change in peripheral vascular resistance and BP.
What is the absorption and fate of dobutamine? What are the therapeutic uses?
Metabolized rapidly, brief duration of action.
Uses: short-term treatment of cardiac decompensation (card surgery, CHF, infarction), cardiac stress testing
What receptors does albuterol act on? How is it administered?
Mainly B2 adrenergic receptors (agonist).
Administered by inhalation or orally. Short acting and rapid onset.
What is the therapeutic use of albuterol? What are some adverse effects?
Used for relief of bronchoconstriction (asthma)
Adverse effects: tremor, anxiety, tachycardia.
What is Salmeterol? How is it given and what’s the duration of action?
A B2 adrenergic receptor agonist given by inhalation.
> 12 hour duration of action.
What is the therapeutic use of Salmeterol? Can it be used for acute bronchospasm?
Chronic obstructive pulmonary disease, moderate to severe persistent asthma.
Slow onset of action so not suitable as monotherapy for acute bronchospasm.