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21 Cards in this Set
- Front
- Back
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prototype mixed action adrenergic agonist? its structure?
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ephedrine
no subs on phenyl. N-methyl alpha-methyl beta-hydroxyl |
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in general, -OH groups on the phenyl ring of agonists have what effect?
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reduced CNS activity & reduce oral bioavailability
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what drug has a direct effect at only alpha1 adrenergic receptors? its structure?
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phenylephrine
one phenyl-OH. N-methyl, beta-OH another drug is methoxamine |
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what drug has a direct effect at only alpha2?
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clonidine
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what drug has a direct effect at only beta1? its structure?
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dobutamine
dopamine with another phenol-butyl type group on dopamine's N. ie huge substituent on the amine |
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what drug has a direct effect at only beta2? its structure?
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terbutaline (also albuterol)
3,5 phenyl-OH, N-tertbutyl, beta-OH |
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amphetamine has no -OH groups on the phenyl, and has an alpha-methyl group. what are the effects of this?
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no OH - orally available, access to CNS
alpha-methyl: resistant to MAO |
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adrenergic receptor locations: alpha1
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Vascular Smooth Muscle, pupillary dilator, pilomotor, prostate, heart (small role)
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adrenergic receptor locations: alpha2
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nerve terminals (inhibitory), fat cells to inhibit lipolysis platelets for aggregation, some VSM for contraction
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adrenergic receptor locations: beta1
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heart
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adrenergic receptor locations: beta2
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brochial SMC, uterus, VSM, liver (glycogenolysis)
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adrenergic receptor locations: beta3
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fat cells for lipolysis
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adrenergic receptor locations: D1
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dilates renal VSM
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adrenergic receptor locations: D2
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nerve terminals - modulates NT release (inhibitory, reduce cAMP levels)
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describe the differences of low [Epi] vs high [Epi] acting on VSM
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Epi binds Beta2 > Alpha1. Both exist on VSM, however, # of alpha1 > # beta2. thus, low [Epi] will vasodilate via beta2, but high [Epi] will reverse effect and vasoconstrict due to alpha1, leading to baroreflex activity and REDUCED heart rate.
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an alpha1 agonist will have what effect on BP and HR? what is the prototypical alpha1 agonist?
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phenylephrine will mostly affect VSM, where alpha1 predominates. this will increase MAP, and HR will drop from baroreflexes
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what Rx would you use to reduce TPR with no immediate change in HR or CO?
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terbutaline/albuterol, beta2agonist
(alpha 1 antagonist? prozasin?) |
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what Rx to increase CO and contractility and VO2 with no change in TPR?
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dobutamine, Beta1 agonist
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dopamine is weird. describe its effects at low doses, then at high doses
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low doses - mainly increases flow to kidney (via D1) and acts on heart Beta1.
high doses - activates alpha1 and increases TPR |
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NE acts on Beta1 and alpha1, leading to increased TPR and BP. what happens to the heart rate and contractility?
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heart rate wants to rise due to NE on Beta1, but baroreflex, via vagal nerves, slow down heart. however, the inotropic effect of NE remains
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regarding NE and Epi, baroreflexes can reverse the Beta1 effects on heart. what beta1 effects are never reversed?
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contractility (inotropic effect) and VO2 are not reversed
-thus baroreflexes-vagus n. can reverse chronotropic effect, but not inotropic effect |
