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Flashcards in CV Stimulants Deck (85)
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1

What are some CV stimulants?

-Epi
-Nor
-Dopamine
-Dobutamine
-Isoproterenol
-Phenylephine
-Ephedrine

2

What does stimulation of beta receptors in the heart (B1) lead to?

-accelerated SA/AV node (HR up)

-accelerated ectopic pacemakers

-increased contractility

3

What does stimulation of beta receptors in skeletal muscle vasculature lead to?

relaxation via preventing the entry of calcium that is critical to the contraction of vascular smooth muscle.

4

What does binding of epinephrine or NE to β adrenoceptors result in?

Stimulates adenylyl cyclase by activating the stimulatory G
protein, Gs, which leads to the dissociation of its alpha subunit charged with GTP. This activated αs subunit directly activates adenylyl cyclase, resulting in an increased rate of synthesis of cAMP.

5

What does binding of epinephrine or NE to a2 adrenoceptors result in?

Binding of presynaptic alpha2-adrenoceptor ligands inhibits adenylyl cyclase by causing dissociation of the inhibitory G protein, Gi, into its subunits; ie, an activated αi subunit charged with GTP and a β-γ unit.

The mechanism by which these subunits inhibit adenylyl cyclase is uncertain.

cAMP binds to the regulatory subunit (R) of cAMP-dependent protein kinase, leading to the liberation of
active catalytic subunits (C) that phosphorylate specific protein substrates and modify their activity.

6

Which receptors are linked to the Gq protein?

a1
M1
M3

7

Which receptors are linked to the Gi protein?

a2
D2
M2

8

Which receptors are linked to the Gs protein?

B1/B2
D1

9

Which sympathomimetic agents act on a-receptors?

-Epi (locally vasoconstrict)
-NE
-DA (at higher dose)
-Dobutamine
-Phenylephrine
-Ephedrine

10

Which sympathomimetic agents act on B-receptors?

-Epi
-DA (at higher dose)
-Dobutamine
-Isoproterenol
-Ephedrine

11

Sympathomimetic drugs are classified based upon their mechanism of action either in the pre-synaptic terminal or on the post-synaptic membrane. What do direct acting drugs do?

stimulate postsynaptic receptors

12

What do indirect acting drugs do?

Indirectly-acting drugs cause an increase of E or NE via:

- causing release from pre-synaptic terminals
- blocking transport into sympathetic neurons (cocaine)
- blocking metabolizing enzymes

13

What are some stimulant metabolizing enzymes?

-monoamine oxidase (MAO)
-catechol-O-methyltransferase (COMT)

14

Drugs that cause a release of neurotransmitter, but they also themselves stimulate the receptors are called what?

mixed-acting drugs

15

What are some direct acting selective adrenergic agonists?

a1-phenylephrine
a2-clonidine
B1-dobutamine
B2-terbutaline

please call dad tomorrow

16

What are some direct acting non-selective adrenergic agonists?

a1/2 oxymetazoline
B1/2 isoproterenol
a1/2, B1/2 Epi
a1/2, B1- Nor

17

T or F. Both selective and non-selective direct acting adrenergic agnostic are not reduced by reserpine pretreatment

T. May actually increase because NE induces changes that up-regulate receptors or enhance signaling pathway

18

What are some mixed acting adrenergic agnostic?

Ephredrine

19

Is Ephredrine reduced by prior treatment with reserpine?

Effects are blunted, but not abolished

20

What are some indirect acting adrenergic agonists?

-Cocaine
-MOAI/COMTI
-Tyramine
-Amphetamine

21

How do MAOIs or COMTIs cause indirect effects?

By preventing the breakdown of released
neurotransmitter

22

How doe Tyramine and Amphetamine cause indirect effects?

cause the release of preformed transmitter that is normally stored successfully in the presynaptic vesicles

23

What does reserpine do?

depletes NE from sympathetic neurons

24

Does pretreatment with reserpine affect the effects of indirect adrenergic agonists?

Yes, abolishes them

25

What is the receptor specificity for Dobutamine?

B1 more than B2, alpha

26

What are the uses of Dobutamine?

HF (ino over chrontropic), stress tests

27

What is the receptor specificity for DA?

D1=D2 more than B more than alpha

28

What are the uses of DA?

-unstable bradycardia
-HF
-shock
-inotropic and chronotropic effects predominate at high doses

29

What is the receptor specificity for Epi?

a1=a2; B1=B2

30

What are the uses of Epi?

-anaphylaxis
-cardiac arrest
-hypotension