Lippincott Adrenergic Agonist

Question 1

6.1 Which of the following is correct regarding adrenergic
neurotransmission?
A. Epinephrine is the major neurotransmitter released
from sympathetic nerve terminals.
B. Norepinephrine is mainly released from the adrenal
glands.
C. Tricyclic antidepressants and cocaine prevent
reuptake of norepinephrine into the nerve terminals.
D. Monoamine oxidase (MAO) converts dopamine to
norepinephrine in the nerve terminal.

Answer 1

Correct answer = C. Tricyclic antidepressants (TCAs) and
cocaine inhibit the transporter protein that prevents the
reuptake of norepinephrine into the sympathetic nerve ter-
minals. Norepinephrine, not epinephrine, is the major neu-
rotransmitter released from sympathetic nerve terminals.
Epinephrine, not norepinephrine, is mainly released from
the adrenal glands. Dopamine is converted to norepineph-
rine by dopamine β-hydroxylase, not by MAO.

Question 2

6.2 All of the following are correct regarding adrenergic
receptors, except:
A. α1
Receptors are primarily located on the
postsynaptic membrane in the effector organs.
B. α2
Receptors are primarily located on the
presynaptic sympathetic nerve terminals.
C. β1
Receptors are found mainly in the heart.
D. β2
Receptors are found mainly in adipose tissue.

Answer 2

Correct answer = D. α1
Receptors are located on the post-
synaptic membrane in the effector organs such as blood
vessels. α2
Receptors are mainly found on the presynaptic
sympathetic nerve terminals, where they inhibit the release
of norepinephrine when activated. β1
Receptors are found
in the heart, in addition to some other tissues, and cause
increase in heart rate and contractility when activated. β2
receptors are found in the lungs, in addition to some other
tissues, and cause relaxation of bronchial smooth muscles
when activated. β3
Receptors are found in adipose tissue
and are involved in lipolysis.

Question 3

6.3 A hypertensive patient was accidentally given an α2
agonist instead of an α1
blocker. Which of the following
is correct in this situation?
A. α2
Agonists can increase the release of
norepinephrine from sympathetic nerve terminals.
B. α2
Agonists can reduce blood pressure in this
patient.
C. α2
Agonists can increase blood pressure in this
patient.
D. α2
Agonists will not affect blood pressure in this
patient.

Answer 3

Correct answer = B. α2
Agonists activate α2
receptors
located in the presynaptic terminal of sympathetic neurons
and cause a reduction in the release of norepinephrine from
sympathetic nerve terminals. This leads to a reduction in
blood pressure. α2
Agonists such as clonidine and methyl-
dopa are therefore used as antihypertensive agents.

Question 4

6.4 Which of the following is correct regarding responses
mediated by adrenergic receptors?
A. Stimulation of α1
receptors increases blood
pressure.
B. Stimulation of α1
receptors reduces blood pressure.
C. Stimulation of sympathetic presynaptic α2
receptors
increases norepinephrine release.
D. Stimulation of β2
receptors increases heart rate
(tachycardia).
E. Stimulation of β2
receptors causes
bronchoconstriction.

Answer 4

Correct answer = A. Stimulation of α1
receptors, mostly
found in the blood vessels, causes vasoconstriction and
increase in blood pressure. Stimulation of α2
receptors on
the sympathetic presynaptic terminal reduces the release
of norepinephrine. β2
receptors are not found in the heart,
so activation of β2
receptors does not affect heart rate.
Stimulation of β2
receptors found in the bronchial tissues
causes bronchodilation, not bronchoconstriction

Question 5

6.5 An asthma patient was given a nonselective β agonist
to relieve bronchoconstriction. Which of the following
adverse effects would you expect to see in this patient?
A. Bradycardia.
B. Tachycardia.
C. Hypotension (reduction in blood pressure).
D. Worsening bronchoconstriction.

Answer 5

Correct answer = B. A nonselective β agonist activates both
β1
as well as β2
receptors. β1
activation causes an increase
in heart rate (tachycardia), contractility, and subsequent
increase in blood pressure. It relieves bronchoconstriction
because of the β2
receptor activation.

Question 6

6.6 Which of the following adrenergic agonists is most
likely to cause CNS side effects when administered
systemically?
A. Epinephrine.
B. Norepinephrine.
C. Isoproterenol.
D. Dopamine.
E. Ephedrine.

Answer 6

Correct answer = E. Ephedrine is more lipophilic compared
to the other drugs listed and therefore is more likely to
cross the blood–brain barrier when administered systemi-
cally. Therefore, ephedrine is more likely to

Question 7

6.7 A 12-year-old boy who is allergic to peanuts was brought
to the emergency room after accidentally consuming
peanuts contained in fast food. He is in anaphylactic
shock. Which of the following drugs would be most
appropriate to treat this patient?
A. Norepinephrine.
B. Phenylephrine.
C. Dobutamine.
D. Epinephrine.

Answer 7

Correct answer = D. Norepinephrine has more α agonis-
tic effects and activates mainly α1
, α2
, and β1
receptors.
Epinephrine has more β agonistic effects and activates
mainly α1
, α2
, β1
, and β2
receptors. Phenylephrine has pre-
dominantly α effects and activates mainly α1
receptors.
Dobutamine mainly activates β1
receptors and has no signif-
icant effects on β2
receptors. Thus, epinephrine is the drug
of choice in anaphylactic shock that can both stimulate the
heart (β1
activation) and dilate bronchioles (β2
activation)

Question 8

6.8 A 70-year-old patient was brought to the emergency
room with a blood pressure of 76/60 mm Hg,
tachycardia, and low cardiac output. He was diagnosed
with acute heart failure. Which of the following drugs
would be the most appropriate to improve his cardiac
function?
A. Epinephrine.
B. Fenoldopam.
C. Dobutamine.
D. Isoproterenol

Answer 8

Correct answer = C. Among the choices, the ideal drug to
increase contractility of the heart in acute heart failure is
dobutamine, since it is a selective β1
-adrenergic agonist.
Fenoldopam is a dopamine agonist used to treat severe
hypertension. Other drugs are nonselective adrenergic
agonists that could cause unwanted side effects.

Question 9

6.9 Which of the following adrenergic agonists is commonly
present in nasal sprays available over-the-counter
(OTC) to treat nasal congestion?
A. Clonidine.
B. Albuterol.
C. Oxymetazoline.
D. Dobutamine.
E. Norepinephrine.

Answer 9

Correct answer = C. Drugs with selective α1
agonistic activ-
ity are commonly used as nasal decongestants because of
their ability to cause vasoconstriction in the nasal vessels.
Oxymetazoline is an α1
agonist and therefore the preferred
drug among the choices as a nasal decongestant. Clonidine
is an α2
agonist, albuterol is a β2
agonist, dobutamine is a
β1
agonist, and norepinephrine is a nonselective adrenergic
agonist.

Question 10

6.10 One of your patients who is hypertensive and gets mild
asthma attacks occasionally bought an herbal remedy
online to help with his asthma. He is not on any asthma
medications currently but is receiving a β1
-selective
blocker for his hypertension. The herbal remedy seems
to relieve his asthma attacks, but his blood pressure
seems to increase despite the β-blocker therapy. Which
of the following drugs is most likely present in the herbal
remedy he is taking?
A. Phenylephrine.
B. Norepinephrine.
C. Dobutamine.
D. Ephedrine.
E. Salmetero

Answer 10

Correct answer = D. Two drugs among the choices that
could relieve asthma are ephedrine and salmeterol, as they
activate β2
receptors in the bronchioles and cause broncho-
dilation. However, salmeterol is a selective β2
agonist and
should not cause an increase in blood pressure. Ephedrine
on the other hand stimulates the release of norepinephrine
and acts as a direct agonist at α- and β-adrenergic receptors,
thus causing an increase in blood pressure. Phenylephrine
(a nonselective α agonist) does not cause bronchodilation.
Norepinephrine is a nonselective adrenergic agonist that
does not have any stimulatory effects on β2
receptors. Also,
norepinephrine is not active when given orally