Adrenergic Drugs Flashcards
Name the steps in the formation of norepinephrine, starting with tyrosine from the blood vessels
1) Tyrosine enters nerve and is converted to dopa by tyrosine hydroxylase
2) Dopa is converted to dopamine by dopa decarboxylase
3) Dopamine is converted to norepinephrine by dopamine beta hydroxylase and VESICLE is formed
4) norepinephrine is stored or released for use in synapse
What are β1’s actions in the heart? In the kidney?
Increases HR/contraction force, increases renin secretion
What are β2’s actions in the arterioles? In the bronchial smooth muscle? In the pregnant uterus?
dilation of blood vessels, relaxation of smooth muscle, and relaxation of uterus
What are β3’s actions in the adipose tissue?
Increases lipolysis
What are α1’s actions in the arterioles? In the veins? In the uterus? In the spleen?
Constriction for all of the above
What are α2’s actions in the presynaptic terminal? In the postsynaptic CNS terminal?
Inhibits NE release, and decreases sympathetic tone respectively
What is D1’s actions in the renal, mesenteric, and cerebral arterioles?
Dilation
How does the effect of epinephrine on blood vessels in skeletal muscle differ depending on the concentration?
Low concentration: β2 dilation
High concentration: α1 constriction
Which drug is most potent at the β1 (contraction of heart) and β2 (relaxation of bronchial smooth muscle) receptors?
A) isoproterenol
B) epinephrine
C) norepinephrine
D) dopamine
A) isoproterenol
And in case you’re wondering, the answer choices are in descending order of potency!
Which drug is most potent at the α1 (vasoconstriction) receptor?
A) isoproterenol
B) dopamine
C) norepinephrine
D) epinephrine
D) epinephrine
The answer choices are in order of increasing potencies
Which drug is most potent at the α2 receptor?
A) epinephrine
B) norepinephrine
C) clonidine
D) isoproterenol
C) clonidine
- Clon > epi > NE»_space; iso
What effect does tyramine or amphetamine have in the synapse?
Indirect adrenergic agonist, releases NE from small cytoplasmic pool (NOT from vesicles)
Something crazy is happening to your patient and they are extremely hypertensive. You realize that all of their organs are in danger. However comma you want to focus solely on getting the blood to their kidneys, brain, and abdomen. To achieve these selective effects, what receptors should you target and what drug should you use?
D1 agonist - fenoldopam
What effect does NE have on the TPR, BP, and HR?
Norepinephrine increases the TPR, which causes a subsequent increase in BP and a compensatory decrease in HR due to baroreceptors
What effects do both epinephrine and isoproterenol have on the TPR, BP, and HR? Which of the two produces more pronounced effects?
TPR is down, BP stays about the same, and HR increases. Isoproterenol produces the larger effect.
KEY POINT: Iso and epi also affect β2 receptors, so the TPR stays low and baroreceptors are not activated