Autonomic Pharm II Flashcards

1
Q

Effects of M2 receptor stimulation?

A

decreased neuronal activity to SA node and decreased atrial contractility (little to no effect on ventricles)

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2
Q

Effects of M3 and M5 receptor stimulation?

A

vasodilation of vasculature by Nitric Oxide production

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3
Q

Mechanism of M2 receptor activation?

A

Gi signaling, inhibition of adenylate cyclase–> decrease cAMP–> hyper-polarization of membrane by opening on inward potassium channels

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4
Q

Mechanism of M3 receptor activation?

A

couples through Gq–> increase IP3 and DAG levels–> increase in PKC and Calcium levels–>excitatory

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5
Q

Where in the heart does parasympathetic activity act?

A

SA and AV nodes

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6
Q

Does vasculature receive parasympathetic innervation?

A

No, but it will respond to exogenous muscarinic agonists/antagonists

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7
Q

Effect of IV acetylcholine on the vasculature?

A

vasodilation via NO synthesis

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8
Q

Effect of IV acetylcholine on damaged vasculature?

A

activation of M3 receptors–> smooth muscle contraction and vasoconstriction

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9
Q

Main effect of Atropine on the heart?

A

To increase heart rate, it is a competitive antagonist of muscarinic Ach receptors (acting mainly in the SA node)

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10
Q

Atropine at low doses?

A

Inhibits presynaptic M1 receptors–> Increase in PS activity (Ach release)–> slight slowing of heart rate

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11
Q

Atropine at higher doses?

A

Blockade of PS inhibitory effects on the SA node leading to progressive tachycardia

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12
Q

Effect of Atropine on the vasculature?

A

Minimal given that most vascular beds lack significant cholinergic innervation

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13
Q

What is Atropine Flush?

A

High doses of Atropine can dilate cutaneous blood vessels in a local area causing flushing of the skin

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14
Q

Atropine indications?

A

Abolish temporary over-activity of the Vagal tone of the heart; facilitates AV node conduction (useful in patients with inferior or posterior wall MIs)

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15
Q

Effect of Beta-2 receptor activation?

A

vasodilation in skeletal muscle vasculature and dilation of bronchial smooth muscle

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16
Q

Effect of Beta-1 receptor activation?

A

Increased heart rate and cardiac contractility; Renin release from JGA in the nephrons

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17
Q

How direct-acting drugs work?

A

stimulate the postsynaptic receptors

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18
Q

How indirect-acting drugs work?

A

stimulate the presynaptic terminal to cause release of Epi or Norepi

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19
Q

What is Tachyphylaxis?

A

Reduction in effect seen with chronic therapy

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20
Q

What are MAOIs and how do they work?

A

Monoamine oxidase Inhibitors, prevent the breakdown of neurotransmitter (indirect)

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21
Q

How does Tyramine and Amphetamine work?

A

cause the release of preformed transmitter from storage in the pre-synaptic vesicles (indirect)

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22
Q

How does Reserpine work?

A

depletes Norepi from presynaptic sympathetic neurons

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23
Q

Would you see any effect with a direct-acting drug if pretreated with Reserpine?

A

Yes, response is not reduced at all. May be increased due to Norepi induced compensatory changes

24
Q

Would you see any effect with an indirect-acting drug if pretreated with Reserpine?

A

No, there are no catecholamines left in the vesicles to release

25
Q

Dobutamine receptor specificity

A

B-1 > B-2,

26
Q

Dopamine receptor specificity

A

D1=D2 > B > a

27
Q

Epinephrine receptor specificity

A

a1=a2 : B1=B2

28
Q

Isoproterenol receptor specificity

A

B1=B2

29
Q

Norepinephrine receptor specificity

A

a1 > a2 > B1

30
Q

Phenylephrine receptor specificity

A

a1 > a2

31
Q

Ephedrine receptor specificity

A

a1 > a2 > B1

32
Q

What drug will produce a widening of pulse pressure?

A

Beta non-specific agonists (Isoproterenol); epinephrine, at low doses it drops the diastolic due to vasodilation of skeletal muscle vasculature (B2)

33
Q

Primary receptor on the heart

A

Beta-1

34
Q

Primary receptor on the lungs

A

Beta-2

35
Q

Which drug is commonly put into SubQ lidocaine and other local anesthetics for vasoconstriction?

A

Epinephrine

36
Q

What drug can demonstrate pro-arrhythmogenic activity and fibrillation

A

Epinephrine

37
Q

Epinephrine effect on the kidneys?

A

increase renal vascular resistance–> reduction of renal blood flow by up to 40%
Also acts on beta-1 receptors in the JGA–> renin secretion–> renin-angiotensin aldosterone axis–> elevated BP

38
Q

Main catecholamine made by most pheochromocytomas?

A

Norepinephrine

39
Q

Main differences in physiologic effects of Epi/Norepi?

A

Epi greatly increases Cardiac output, Norepi does not. Norepi increases the blood pressure much more than Epi

40
Q

Synthesis of catecholamines from precursors?

A

Tyrosine–> Dopa–> Dopamine–> Norepi–> Epi

41
Q

Dopamine effect at low dose?

A

Predominately D1 action; potent renal vasodilation–> improves GFR (critical in patients with renal hypo-perfusion)

also vasodilates mesenteric, coronary, and intracerebral vasculature

42
Q

Dopamine effect at moderate dose?

A

D1 + B1 action; increase in Cardiac output (contractility&raquo_space; HR) and D1 induced vasodilation

43
Q

Dopamine effect at high dose?

A

alpha-agonism; increased peripheral vascular resistance and renal vasoconstriction

44
Q

Dobutamine effects/indications?

A

increased CO and stroke volume without much effect on HR; used for short term tx following cardiac decompensation (CHF, Acute MI)

45
Q

Isoproterenol affects these receptors?

A

Beta-1 and Beta-2

46
Q

Isoproterenol effects?

A

Large increase in CO, decrease in diastolic BP due to vasodilation of skeletal muscle vasculature (decreased PVR)

47
Q

Isoproterenol indications?

A

emergencies to stimulate the HR like complete heart block or bradycardia

48
Q

Dobutamine acts on which receptors?

A

B-1 agonist, DOES NOT act on dopamine receptors; ultra short half-life (2 minutes)

49
Q

Effects/indications of Phenylephrine?

A

Potent vasoconstriction, used to manage emergent hypotension; may produce reflex vasovagal bradycardia

50
Q

Ephedrine receptor specificity?

A

Direct agonist at both alpha and beta receptors

51
Q

Effects of Ephedrine?

A

Enhances Norepi release at sympathetic neurons, increases HR, CO, and peripheral resistance

52
Q

Indications for Ephedrine?

A

Asthma and bronchospasm, stimulates beta receptors in the bronchiolar smooth muscle

53
Q

Route of administration of Ephedrine?

A

Oral

54
Q

Adverse effects of Ephedrine?

A

Fatal arrhythmias, including V-fib

55
Q

Regulation of Ephedrine?

A

Active ingredient in OTC cold and sinus products, main precursor to methamphetamine (GO VOLS) (East TN speed dragon)