Lecture 4: Adrenergic Drugs Flashcards Preview

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Flashcards in Lecture 4: Adrenergic Drugs Deck (42)
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What are two Alpha Agonist drugs? (PC) What receptors are they specific for?

phenylephrine a1 > a2

clonidine a2 > a1


What are two mixed Alpha/Beta Agonist drugs? (NE) What receptors do they like to bind to?

norephinephrine and epinephrine

NE --> a1 = a2 and B1 >> B2
E --> a1 = a2 and B1 = B2


What are three Beta Agonist drugs? (DIA) What receptors to they utilize?

dobutamine --> B1 > B2

isoproterenol --> B1 = B2

albuterol --> B2 > B1


What indirect adrenomimetic drug inhibits the re-uptake of dopamine and norephinephrine?



What two indirect adrenomimetic drugs are inhibitors of MAO? (SP)

selegiline and phenelzine


What three indirect adrenomimetic drugs reverse norepinephrine and dopamine mechanisms, and increase their release? (AMT)

amphetamines, methylphenidate, and tyramine (not a drug)


What drug is a releasing agent AND a direct adrenergic receptor agonist?



What G protein does the alpha 1 receptor type use and what are its effects?

- uses Gq

- inc. IP3 and DAG common to all


What G protein does the alpha 2 receptor type use and what are its effects?

- uses Gi

- dec. cAMP common to all


What G protein does the beta receptor type use and what are its effects?

- uses Gs

- inc. cAMP common to all


What G proteins do dopamine receptors D1 and D2 use and what are their effects?

D1 uses Gs = inc. cAMP
D2 uses Gi = dec. cAMP


What is epinephrines selectivity for receptors vs norephinephrines selectivity for receptors?

E --> a1 = a2 and B1 = B2
NE --> a1 = a2 and B1 >> B2


What is epinephrines effect on cardiac function and what receptor does it use?

- uses B1

- inc. force of contraction, HR, and AV node conductivity


What is epinephrines effect on vascular tone and what receptors does it use?

- uses B2 and a1

- inc. systolic BP, may dec. diastolic BP and TPR, mean arterial pressure stays the same


What receptor type, when stimulated, inc. renin release?

B1 (mainly found on heart and juxtaglomerular cells)


What do D1 and D2 receptors do when activated?

D1 = dilates renal blood vessels (on SM)
D2 = modulate transmitter release from nerve endings


What do B3 receptors do when activated? (2)

on bladder (relax detrusor muscle) and on fat cells (activates lipolysis)


What are epinephrines 2 effects on the respiratory system and what receptors does it bind to?

1. relaxes bronchial muscles (B2)

2. dec. bronchial secretion/congestion (a1)


What are the 3 locations for B2 receptors and what are their actions? (SSL)

1. Resp/uterine/vascular SM - relaxation

2. Skeletal muscle - potassium uptake

3. Liver - glycogenolysis and gluconeogenesis


What are the 4 locations for a1 receptors and what are their actions? (VPPH)

1. most vascular SM (innervated) - contraction

2. pupillary dilator muscle - contraction

3. prostate - contraction

4. heart - inc. force of contraction


What are the 5 locations for a2 receptors and what are their actions? (NPNVF)

1. Neurons - modulate transmitter release

2. Platelets - aggregation

3. nerve terminals - inhibit transmitter release

4. some vascular SM - contraction

5. fat cells - inhibit lipolysis


What is norepinephrines effect on the heart and blood vessels?

potent cardiac stimulate (reduces HR --> baroreflex) and vasoconstrictor

- inc. peripheral vascular resistance and BP


What are the two functions of phenylephrine?

- effective mydriatic (pupil dilator) and decongestant

- causes severe vasoconstriction, BP inc., and bradycardia (baroreflex in response)


What is major function of clonidine?

- central effect on presynaptic a2 receptors in lower brainstem that helps regulate NE release

- dec. sympathetic outflow, reduce BP, cause bradycardia

- local application = vasoconstriction


What are the two functions of isoproterenol?

- inc. cardiac output (B1)

- vasodilator and bronchodilation (B2)


What are the functions of dobutamine and albuterol?

D - potent inotropic action (less prominent chronotropic effect compared to isoproterenol)
- some a1 activity (- = agonist, + = antagonist)

A - bronchodilation


What is the importance of Tyramine?

- does NOT cross BBB (hydrophilic, unlike rest of indirect drugs)

- elevates systolic blood pressure (intravenously) and is used in pressor tests to evaluate peripheral adrenergic function


What are common adverse effects of indirect acting lipophilic drugs on the central nervous system?

- insomnia, lack of appetite, anxiety, paranoia, convulsions and hemorrhagic stroke


What are two non-selective alpha receptor antagonists? (PP)

phentolamine (reversible competitive; short acting)

- non-competitive, irreversible; long acting


What are 3 a1 receptor selective antagonists? (PTD)

prazosin, tamsulosin, doxazosin