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Pharmacology > Module 2 Sympathomimetics > Flashcards

Module 2 Sympathomimetics Flashcards

1
Q

The ultimate effects of sympathetic stimulation are mediated by release of what neurotransmitter?

A

Norepinephrine

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2
Q

In responseto a variety of stimuli such as stress, the adrenal medulla releases this substance which is transported into the blood to target tissues

A

Epinephrine

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3
Q

What do you call the drugs that mimics the actions of epinephrine or norepinephrine?

A

Sympathomimetic Drugs

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4
Q

These drugs directly interact with and activate adrenoreceptors

A

Direct agonists

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5
Q

These drugs’ actions are dependent on their ability to enhance the actions of endogenous cathecolamines

A

Indirect agonists

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6
Q

2 mechanisms of Indirect Agonists

A
  1. They may displace stored catecholamines from the adrenergic nerve ending, or they may decrease clearance of released norepinephrine by:
    2a. Inhibiting reuptake if catecholamines already released
    2b. Preventing enzymatic metabolism of norepinephrine
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7
Q

True or False: both types of sympathomimetics, both direct and indirect, ultimately cause inactivation of adrenoreceptors

A

False. Activation

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8
Q

The pharmacologic effects of indirect sympathomimetics are greater under what conditions?

A

Increased sympathetic activity and norepinephrine storage and release

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9
Q

The effects of catecholamines are mediated by what type of cell-surface receptors?

A

G protein-coupled receptors

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10
Q

What are the G proteins that are of particular importance for adrenoreceptor function?

A

Gs, Gi, Go, Gq, G11

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11
Q

What g protein stimulates adenylyl cyclase?

A

Gs

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12
Q

This g protein inihibits adenylyl cyclase

A

Gi & Go

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13
Q

These g proteins couple the alpha receptors to phospholipase c

A

Gq & G11

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14
Q

Give the effectors of adrenoreceptor-activated alpha units

A

Adenylyl cyclase
cGMP phosphodiesterase
Phospholipase C
Ion channels

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15
Q

To which substances are the alpha receptors potent to

A

Epinephrine>Norepinephrine»»»Isoprotenol

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16
Q

To what substances are beta receptors potent to

A

Isoprotenol>epinephrine>norepinephrine

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17
Q

Alpha receptors are coupled via g proteins in what family? To what are they coupled to?

A

Gq

Phospholipase C

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18
Q

Phospholipase C hydrolizes polyphosphoinositides leading to formation of what?

A

Inositol 1,4,5-triphosphate (IP3)

Diacylglycerol (DAG)

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19
Q

This promotes the release of sequestered Ca2+ from intracellular stores, which increase cytoplasmic free Ca2+ concentrations that activate various calcium-dependent protein kinases.

A

IP3

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20
Q

This receptor activate signal transduction pathways that stimulate tyrosine kinases

A

Alpha 1 receptors

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21
Q

These receptors are coupled to the inhibitory protein Gi that inhibiys adenylyl cyclase activity and cause intracellular cAMP levels to decrease

A

Alpha 2 receptors

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22
Q

These agonists cause platelet aggregation and a decrease in platelet cAMP levels

A

Alpha 2 receptor agonists

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23
Q

Activation of all three receptor subtypes of Beta receptors results in ______

A

Stimulation of adenylyl cyclase and increased cAMP

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24
Q

In the liver, beta-receptor-activated cAMP synthesis leads to a cascade of events culminating in activation of what enzyme?

A

Glycogen Phosphorylase

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25
Q

In the heart, beta-receptor-activated cAMP synthesis leads to increase in what?

A

Increase the influx of Calcium

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26
Q

Beta receptor activation also promotes ____ of the smooth muscles

A

Relaxation

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27
Q

Which beta receptor is a low affinity receptor and is more resistantto desensitization

A

Beta 3

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28
Q

Beta 3 is expressed in the detrussor muscle of the bladder and induces its ______

A

Relaxation

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29
Q

What selective beta 3 agonist has been recently been approved as tx of symptoms of overactive bladder?

A

Mirabegron

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30
Q

This dopamine receptor is associated with stimulation of adenylyl cyclase

A

D1

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31
Q

D1-receptor-induced smooth muscle relaxation is due to what mechanism

A

cAMP accumulation in the smooth muscle

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32
Q

This dopamine receptor inhibits adenylyl cyclase activity, open patassium channels, and decrease calcium influx.

A

D2

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33
Q

This term means that a drug preferentially bind to one group of receptors at concentrations too low to interact intensivelywith another subgroup.

A

Selectivity

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34
Q

True or false: the effects of a given drug is independent of its selectivity to adrenoreceptor types and to the relative expression of receptor subtypes in a given tissue

A

False. Effects are DEPENDENT on these

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35
Q

After a cell or tissue has been exposed for a period of time to an agonist, that tissue often becomes less responsive to further stimulation by that agent.

What is this phenomenon called

A

Desensitization

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36
Q

Desensitization is significant because it may limit the therapeutic response to sympathomimetic agents. True or False

A

True

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37
Q

One of the two major categories of desensitization wherein the loss of responsiveness exclusively of receptors have been exposed to repeated or sustained activatoom by an agonist

A

Homologous desensitization

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38
Q

This ANS is an important regulator of virtuallyall organ systems

A

Sympathetic nervous system

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39
Q

This kind of sensitization refers to the process by which desensitization of one receptor by its agonist also results in desensitization of another receptor that has not been directly activated by the agonist in question

A

Heterologous Desensitization

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40
Q

These agonists selectively activate the arrestin-coupled signalling pathways

A

Biased agonists

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41
Q

The principal mechanism for removal of norepinephrine

A

Norepinephrine Transporter

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42
Q

In the heart, how much Norepinephrine is removed by NET?

A

90%

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43
Q

In the vasculature, how much norepinephrine is removed by NET?

A

60%

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44
Q

The remaining synaptic norepinephrine (not removed by NET) may escape into the extrasynaptic space and eneter the bloodstream or be taken up into extra neuronal cells and metabolized by what enzyme?

A

Catechol-O-methyltransferase (COMT) [sa heart]

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45
Q

Norepinephrine may reenter cells or undergo metablosim by what enzyme?

A

Monoamine Oxidase (MAO) [sa vasculature galing yung norepi]

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46
Q

The NET has equivalent affinity for _____ as for norepinephrine

A

Dopamine

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47
Q

This can sometimes clear dopamine in the brain areas where DATis low, like the cortex.

A

NET

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48
Q

What is the parent compound from which sympathomimetic drugs are derived?

A

Phenylethylamine

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49
Q

Alpha 1 receptors are widely expressed in vascular beds leading to arterial ________ and venous ______

A

Arterial and venous vasoconstriction

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50
Q

A pure alpha agonist increases….

A

Peripheral arterial resistance and decreases venous capacitance

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51
Q

True or false: any effect agents have on blood pressure is counteracted by compensatory autonomic baroreflex mechanisms aimed at restoring homeostasis.

A

True

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52
Q

Alpha 1 receptor stimulation leads to a rise in BP. However, this elicits a baroreceptor-mediated increase in….

A

Vagal tone + slowing of the heart

But! CO is not diminished because increased VR may increase stroke volume

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53
Q

Skin vessels have predominantly _________ receptors and constrict in response to epinephrine and norepinephrine, as do the splanchic vessels.

A

Alpha receptors

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54
Q

This receptor is present in the vasculature and their activation leads to vasoconstriction. However, they should be given locally via IV or in very high oral doses for the effects to be observed.

A

Alpha 2

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55
Q

Alpha 2 agonists can be used as ______ in the tx of hypertension

A

Sympatholytics

56
Q

Stimulation of this kind of receptor in the heart increases CO by increasing contractility and direct activation of the Sinus node to increase HR.

A

Beta receptors

57
Q

Beta atonists also increase peripheral resistance by activating beta 1 receptors, leading to vasoconstriction in certain vascular beds.

True or false

A

False. Decrease peripheral resistance

Vasodilation

58
Q

What is the net effect of beta receptor activation?

A

Maintain or slightly increase sustolic pressure and to lower diastolic pressure so that the mean bp is decreased

59
Q

Beta receptor activation results in increased calcium influx in cardiac cells. This leads to:

A

Sinoatrial Node and Purkinje fibers is increased: + Chronotropic effect
Atrioventricular node velocity is increased : + dromotropic effect
Intrinsic contractility is increased: + inotropic effect

60
Q

Physiolic stimulation of the heart by catecholamines tends to…

A

Increase coronary blood flow

61
Q

Intravenous administration of dopamine promotes _____ of renal, splanchic, coronary, cerebral, etc via activation of D1 receptors

A

Vasodilation

62
Q

Effect of d1 receptor activation in renal vasculature

A

Natriuresis

63
Q

The renal effects of dopamine have been used clinically to improve ______

A

Perfusion to the kidney in situations of oliguria

64
Q

Dopamine also activates the _____ receptors in the heart. At low does, peripheral resistance may _______. At high doses, it activates alpha receptors leading to _____. High doses may mimic the actions of _______

A

Beta 1
Decrease
Vasoconstriction
Epinephrine

65
Q

Beta 2 receptor activation in bronchial smooth muscles leads to….

A

Bronchodilation

Thus, very important in the tx of asthma

66
Q

Radial pupillary dilator muscle of the iris contains ______ receptor; activation by phenylephrine causes mydriasis

A

Alpha receptors

67
Q

Alpha ____ agonist increase the outflow of aqueous humor from the eye and can be used clinically to reduce IOP.

A

Alpha 2

68
Q

Beta antagonists ______ production of aqueous humor

A

Decrease

Therefore they are used in the tx of Glaucoma

69
Q

The bladder base, urethral sphincter, and prostate contains this type of receptor. These mediate contraction and promote urinary continence

A

Alpha 1a

70
Q

This receptor is found in the ductus deferens, seminal vesicle, and prostate, and plays a role in normal ejaculation

A

Alpha receptor

71
Q

Detumescence of erectile tissue is brought about by what substance

A

Norepinephrine

72
Q

Activation of beta adrenoreceptors in fat cells leads to…

A

Increased lipolysis with enhanced release of FFA and Glycerol into the blood

73
Q

Human fat cells also contain alpha 2 receptors which….

A

Inhibit lipolysis by decreasing intracellular cAMP

74
Q

Catecholamines in high concentration leads to…

A

Metabolic Acidosis

75
Q

Insulin secretion is mediated by…

And inhibited by…

A

Beta receptors

Alpha 2 receptors

76
Q

This is both an alpha and beta agonist. It is a potent vasoconstrictor and cardiac stimulant. It has + inotropic and chronotropic actions on the heart

A

Epinephrine

77
Q

Epinephrine also activates beta 2 receptors in skel ms blood vessels leading to…

A

Dilation

78
Q

Alpha 1 and alpha 2 agonist. Also activates beta 1. Increases tpr and both diastolic and systolic bp.

A

Norepinephrine

79
Q

Immediate precursor of norepinephrine. Involved in the reward stimulus relevant to addiction. Its deficiency in the basal ganglia leads to Parkinson’s disease

A

Dopamine

80
Q

This is not a catechol derivative therefore it is not inactivated by COMt and has a longer duration of action. It is an effective mydriatic and decongestant and can be used to raise BP

A

Phenylephrine

81
Q

This is a prodrug that is enzymatically hydrolyzed to desglymidodrine, a selective alpha 1 receptor agonist. This is used for the tx of orthostatic hypotension. But it may cause hypertension when subject is supine

A

Midodrine

82
Q

Alpha 2 selective agonists _______ blood pressure thru actions in the CNS that _____ sympathetic tone.

A

Decrease

Reduce

83
Q

For sedation and intensive care setting before anesthesia. It reduces the requirements for opioids in pain control.

A

Dexmedetomidine

84
Q

This is a centrally acting muscle relaxant

A

Tizanidine

85
Q

Very potent beta receptor agonist. Has positive chronotropic and inotropic actions. Also a potent vasodilator. Leads to increased CO, fall in diastolic and MAP, and a lesser decrease in systolic pressure

A

Isoproterenol

86
Q

Beta 1 selective agonist has these effects…

A

Increased CO

Less reflex tachycardia

87
Q

Has a positive inortropic actiom. Greater inotropic than chronotropic effect vs isoproterenol.

A

Dobutamine

88
Q

First orally active sympathomimetic drug. Has high bioavailability and relatively long duration of action

A

Ephedrine

89
Q

This is composed of a catechol nucleus + amine + sidechain

A

Catecholamines

90
Q

What are the natural catecholamines?

A

Epinephrine, norepinephrine, dopamine

91
Q

What are the synthetic catecholamines?

A

Dobutamine… Tska may isa pa huhu di ko sure basta Iso something

92
Q

This kind of uptake is specific for norepi. This is found at the neuronal membrane and inhibited by Cocaine, TCAD, amphetamines.
This uptake is towards the terminal bulb

A

Uptake I

93
Q

This kind of uptake is less specific and is towards the tissue. It is found on smooth and cardiac muscles. It has no pharmacologic importance.

A

Uptake II

94
Q

This type of metabolism happens intracellularly (@ the mitochondrial membrane) and at the norepinephrine terminals at the liver & intestines.

A

Mono Amine Oxidase (MAO)

95
Q

This metabolism inhibitor is used as antidepressants.

In depression, there is a decrease in catecholamines, so we use these drugs to increase this level.

A

MAO inhibitors

96
Q

This enzyme is found on neuronal and non-neuronal tissue. This metabolizes catecholamines and their byproducts

A

COMT

97
Q

These receptors decrease insulin secretion

A

Alpha 2

98
Q

This receptor increases renin secretion

A

Beta 1

99
Q

This receptor decreases renin secretion

A

Alpha 2

100
Q

This is a potent vasoconstrictor and cardiac stimulant. But, this causes vasodilation in skeletal muscles to increase blood flow during exercise

A

Epinephrine

101
Q

This acts on both alpha 1 and alpha 2 to increase total peripheral resistance and thus, increase systolic and diastolic BP

A

Norepinephrine

102
Q

This is a pure alpha 1 agonist and is not inactivated by COMT thus it has a longer duration of action. It is also a mydriatic agent, decongestant, and it increases Bp

A

Phenylephrine

103
Q

This is a prodrug that targets alpha 1 receptors. This is used as tx for orthostatic hypotension due to impaired ANS dysfunction.

A

Midodrine

104
Q

This is like phenylephrine. This cause prolonged increase in BP and vagally mediated bradycardia.

A

Methoxamine

105
Q

This drug if discontinued abruptly could cause rebound hypertension. This is an alpha 2 selective agonist

A

Clonidine

106
Q

This is used for sedation of intubated pand mechanically ventilated patients

A

Dexmedetomidine

107
Q

This is contraindicated for pre-eclampsia

A

Methyldopa

108
Q

This is a beta agonist and has positive chronotropic and inotropic effects. This exclusively acts on beta receptors inducing vasodilation and thus increasing cardiac output

A

Isoproterenol

109
Q

This is a beta 1 selective drug that has the same structure with dopamine. It has a positive inotropic effect

A

Dobutamine

110
Q

This is the first orally active drug from the ma huang plant. It has high bioavailability and long duration of action. This is used for tx of asthma

A

Ephedrine

111
Q

This is a mixed acting drug that is a common decongestant. This is a component of metamphetamine

A

Pseudoephrine

112
Q

This is a mixed acting drug that is used as appetite suppressant and decongestant. This is associated with hemorrhagic stroke in females and can increase BP

A

Phenylpropanolamin

113
Q

This is an indirect-acting sympathomimetic that stimulates the CNS. It is similar to ephedrine and increases mood & alertness while decreasing appetite. Its action is mediated via release of norepi

A

Amphetamines

114
Q

This is used for children with ADHD. This has a paradoxic effect. This must be given before bedtime. Can cause cross stunting of growth

A

Methylphenidate

115
Q

This increases the concentration of epinephrine, dopamine, serotonin, and glutamate while decreasing GABA levels. This improves wakefulness in narcolepsy. This can also increase BP and HR

A

Modafinili

116
Q

This has high concentrations in fermented food. It is a byproduct of tyrosine metabolism and may cause increase in BP when taken with MAO inhibitors

A

Tyramine

117
Q

This is a selective inhibitor of Norepinephrine reuptake and potentiate NE levels. This is also a tx for Pnoy este ADHD

A

Atomoxetine

118
Q

This is the only FDA approved drug for the tx of obesity

A

Sibutramine

119
Q

This is used as local anesthetics and inhibits dopamine reuptake. This can be smoked, snorted, or injected. This has an amphetamine-like effect tho shorter but more intense

A

Cocaine

120
Q

This is used as tx for Parkinson’s disease. Can readily pass the blood brain barrier.

A

Levodopa

121
Q

This is a D1 agonist. It causes vasodilation and is used as tx for severe Hypertension

A

Fenoldepam

122
Q

What drugs are used for acute hypotension?

A

Norepinephrine, phenylephrine, methoxanine

123
Q

What drugs are used for CardiogenicShock and AHF. These aim to optimize perfusion not bp

A

Dopamine and dobutamine

124
Q

These drugs are used for chronic orthostatic hypertension by increasing total peripheral resistance

A

Midodrine, ephedrine, phenylephrine

125
Q

What are used for emergency management of complete heart block amd cardiac arrest?

A

Isoproterenol & epinephrine

Epinephrine redistribute blood to the brain and heart

126
Q

These are used to induce local vasoconstriction. These are used during oral, facial, and nasopharyngeal surgery

A

Epinephrine and cocaine

127
Q

What is the non selective drug for bronchial asthma?

A

Epinephrine

128
Q

What is the beta selective drug for bronchial asthma?

A

Isoproterenol

129
Q

These are beta-2 selective drug used for bronchial asthma

A

Albuterol, metaproterenol, terbutaline

130
Q

This is used as initial tx for anaphylaxis

A

Epinephrine

131
Q

These are used for tx of anaphylaxis

A

Glucocorticoids and antihistamine

132
Q

What are the tx for narcolepsy

A

Amphetamine and modafinil

133
Q

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

A

C

134
Q

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

A

D

135
Q

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

A

B

Pharmacology (12 decks)

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