Pharma - Autonomic Drugs (Part 1) Flashcards Preview

USMLE (S1) Pharmacology > Pharma - Autonomic Drugs (Part 1) > Flashcards

Flashcards in Pharma - Autonomic Drugs (Part 1) Deck (127)
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1
Q

From which regions of the central nervous system do parasympathetic nerves originate?

A

Cranial and sacral regions

2
Q

From which regions of the central nervous system do sympathetic nerves originate?

A

Thoracic and lumbar regions

3
Q

What types of nerves arise from the spinal cord and innervate skeletal muscle directly?

A

Somatic nerves

4
Q

How many neurons are involved in parasympathetic transmission from the spinal cord to the target organ?

A

Two

5
Q

True or False? Craniosacral parasympathetic axons synapse on neurons in the peripheral ganglia.

A

TRUE

6
Q

What neurotransmitter mediates parasympathetic nervous system function?

A

Acetylcholine

7
Q

What neurotransmitter receptor mediates parasympathetic nervous system function at the peripheral ganglia?

A

Nicotinic acetylcholine receptors

8
Q

What neurotransmitter receptor mediates parasympathetic tone in the cardiac muscle?

A

Muscarinic acetylcholine receptors (specifically, M2)

9
Q

What neurotransmitter receptor mediates parasympathetic tone in the smooth muscle?

A

Muscarinic acetylcholine receptors (specifically, M3)

10
Q

What neurotransmitter receptor mediates parasympathetic tone in the glandular cells?

A

Muscarinic acetylcholine receptors (specifically, M1 and M3)

11
Q

Somatic nerves that arise from the spine innervate skeletal muscle. What neurotransmitter receptor, which is located on skeletal muscle, receives this input?

A

Nicotinic acetylcholine receptors

12
Q

How many neurons are involved in sympathetic transmission from the spinal cord to the target organ?

A

Two

13
Q

Where is the first synapse after the spinal cord in sympathetic innervation of an organ?

A

Preganglionic sympathetic axons synapse on neurons in the paravertebral ganglia

14
Q

True or False? Preganglionic sympathetic axons synapse on neurons in the peripheral ganglia.

A

FALSE

preganglionic sympathetic axons synapse on neurons in the paravertebral ganglia

15
Q

At the paravertebral ganglia, the neurotransmitter _____ acts on _____ receptors to mediate sympathetic nervous system function.

A

Acetylcholine; nicotinic acetylcholine

16
Q

What neurotransmitter mediates sympathetic nervous system function at the sweat glands?

A

Acetylcholine

17
Q

What neurotransmitter receptor mediates sympathetic nervous system function at the sweat glands?

A

Muscarinic acetylcholine receptors

18
Q

What neurotransmitter mediates sympathetic tone in the cardiac muscle, smooth muscle, and glandular cells?

A

Norepinephrine

19
Q

What are four cell types in which α- and β-adrenergic receptors mediate sympathetic tone?

A

Cardiac muscle, smooth muscle, glandular cells, and terminal ends of neurons

20
Q

What neurotransmitter mediates sympathetic tone in the renal vascular smooth muscle?

A

Dopamine

21
Q

What neurotransmitter receptor mediates sympathetic tone in the renal vascular smooth muscle?

A

D1 receptors

22
Q

What two substances are released into the blood from the adrenal medulla after the activation of the sympathetic nervous system?

A

Epinephrine and norepinephrine

23
Q

How many synapses are involved in activation of the adrenal medulla?

A

One

the adrenal medulla releases epinephrine and norepinephrine into the blood

24
Q

Are nicotinic acetylcholine receptors ligand-gated sodium-potassium channels or G-protein coupled receptors?

A

Nicotinic receptors are ligand gated sodium-potassium channels

25
Q

Are muscarinic acetylcholine receptors ligand-gated sodium-potassium channels or G-protein-coupled receptors?

A

Muscarinic acetylcholine receptors are G-protein-coupled receptors that act through second messengers

26
Q

To what class of G-proteins are α1-receptors linked?

A

q

27
Q

To what class of G-proteins are α2-receptors linked?

A

i

28
Q

To what class of G-proteins are β1-receptors linked?

A

s

29
Q

To what class of G-proteins are β2-receptors linked?

A

s

30
Q

To what class of G-proteins are M1-receptors linked?

A

q

31
Q

To what class of G-proteins are M2-receptors linked?

A

i

32
Q

To what class of G-proteins are M3-receptors linked?

A

q

33
Q

To what class of G-proteins are D1-receptors linked?

A

s

34
Q

To what class of G-proteins are D2-receptors linked?

A

i

35
Q

To what class of G-proteins are H1-receptors linked?

A

q

36
Q

To what class of G-proteins are H2-receptors linked?

A

s

37
Q

To what class of G-proteins are V1-receptors linked?

A

q

38
Q

To what class of G-proteins are V2-receptors linked?

A

s

39
Q

What are the major effects of α1-receptor activation?

A

It increases vascular smooth muscle contraction, and increases pupillary dilator muscle contraction (mydriasis)

40
Q

What are the major functions of α2-receptor activation?

A

It decreases sympathetic outflow and decreases insulin release

41
Q

What are the major functions of β1-receptor activation?

A

It increases heart rate and contractility, increases renin release from the kidneys, and increases lipolysis of adipose tissue

42
Q

What is the major function of β2-receptor activation on the body's vasculature?

A

Vasodilation

43
Q

What is the major function of β2-receptor activation on the respiratory system?

A

Bronchodilation

44
Q

What effect does β2-receptor activation have on glucagon release?

A

It increases glucagon release

45
Q

Where are M1-receptors located?

A

The central nervous system

46
Q

What effect does M2-receptor activation have on cardiac function?

A

It decreases heart rate and contractility

47
Q

What are the effects of M3-receptor activation?

A

Increased exocrine gland secretions, gut peristalsis, bladder contraction, bronchoconstriction, miosis, and accommodation

48
Q

What effect does D1-receptor activation have on renal vasculature?

A

It relaxes renal vascular smooth muscle

49
Q

What are the effects of H1-receptor activation?

A

Pruritis, pain, nasal and bronchial mucus production, contraction of bronchioles

50
Q

What is the effect of H2-receptor activation?

A

It increases gastric acid secretion

51
Q

What effect does V1-receptor activation have on vascular smooth muscle?

A

It increases vascular smooth muscle contraction

52
Q

The activation of what two types of G-protein-coupled receptors can increase vascular smooth muscle contraction? Which receptors mediate vascular relaxation?

A

α1- and V1-receptors increase contraction; relaxation is mediated by β2, and D1 (renal only)

53
Q

What is the effect of V2-receptor activation? Where are they located?

A

It increases water permeability and reabsorption in the collecting tubules of the kidney

54
Q

What five types of receptors are coupled with Gq proteins?

A

α1, M1, M3, H1, and V1

55
Q

What five types of receptors are coupled with Gs proteins?

A

β1, β2, D1, H2, and V2

56
Q

What three types of receptors are coupled with Gi proteins?

A

a2, M2, and D2

57
Q

What enzyme is activated directly downstream of Gq-coupled receptors?

A

Phospholipase C

58
Q

What enzyme is activated directly downstream of Gs-coupled receptors?

A

Adenyl cyclase

59
Q

What enzyme is inhibited directly downstream of Gi-coupled receptors?

A

Adenyl cyclase

60
Q

Adenyl cyclase catalyzes the conversion of adenosine triphosphate into what molecule?

A

cAMP

61
Q

What final effector enzyme is activated by receptors that are coupled with Gs proteins?

A

Protein kinase A

62
Q

What final effector enzyme is inhibited by receptors that are coupled with Gi proteins?

A

Protein kinase A

63
Q

Phospholipase C catalyzes the cleavage of membrane lipids into what molecules?

A

Inositol trisphosphate3 and diacylglycerol

64
Q

What is the effect of increased inositol triphosphate on the intracellular concentration of calcium?

A

It increases the intracellular calcium concentration

65
Q

What enzyme is activated by diacylglycerol?

A

Protein kinase C

66
Q

What pharmacologic agent blocks the uptake of choline into cholinergic nerve terminals?

A

Hemicholinium

67
Q

What enzyme is responsible for the formation of acetylcholine? What are its two substrates?

A

Choline acetyltransferase; Acetyl-CoA and choline

68
Q

What pharmacologic agent blocks the transport of acetylcholine into the presynaptic vesicles in nerve terminals?

A

Vesamicol

69
Q

The entry of what ion into the nerve terminal induces the release of acetylcholine into the synaptic cleft?

A

Calcium

70
Q

What toxin inhibits the calcium-induced release of acetylcholine from the cholinergic nerve terminals?

A

Botulinum

71
Q

What enzyme breaks down acetylcholine in the synaptic cleft? What two products result from this reaction?

A

Acetylcholinesterase; choline and acetate

72
Q

Tyrosine transporters are located in the nerve terminals of what type of cells?

A

Noradrenergic cells; tyrosine is the precursor of norepinephrine

73
Q

Tyrosine is a precursor to the formation of which neurotransmitters? What is the order of their synthesis?

A

Tyrosine, DOPA, dopamine, norepinephrine, epinephrine

74
Q

What pharmacologic agent blocks the conversion of tyrosine to DOPA?

A

Metyrosine

75
Q

Tyrosine is converted into dopamine via what intermediate precursor?

A

DOPA; DOPA can be used as a pharmacologic agent to increase central nervous system dopamine

76
Q

What pharmacologic agent blocks the transport of dopamine into the presynaptic vesicles in nerve terminals?

A

Reserpine

77
Q

Dopamine is converted into norepinephrine in the ______ (cytoplasm/presynaptic vesicle).

A

Presynaptic vesicles

78
Q

The entry of what ion into the nerve terminal induces the release of norepinephrine into the synaptic cleft?

A

Calcium

79
Q

What pharmacologic agent inhibits the calcium-induced release of norepinephrine from the noradrenergic nerve terminals?

A

Guanethidine

80
Q

What pharmacologic agent stimulates the release of norepinephrine from the noradrenergic nerve terminals?

A

Amphetamine

81
Q

How is norepinephrine cleared form the synaptic cleft?

A

Diffusion, metabolism (monoamine oxidase A), and reuptake

82
Q

What pharmacologic agents inhibit the reuptake of norepinephrine into the nerve terminals?

A

Cocaine, amphetamine, and tricyclic antidepressants

83
Q

What three receptor types modulate the presynaptic release of norepinephrine from the noradrenergic nerve terminals?

A

M2-receptors, angiotensin II receptors, and α2-receptors

84
Q

What effect does the activation of α2-receptors in presynaptic sympathetic nerve terminals have on norepinephrine release?

A

It inhibits norepinephrine release

85
Q

What effect does the activation of angiotensin II receptors in presynaptic sympathetic nerve terminals have on norepinephrine release?

A

It stimulates norepinephrine release

86
Q

What effect does the activation of M2-receptors in presynaptic sympathetic nerve terminals have on norepinephrine release?

A

It inhibits norepinephrine release

87
Q

The norepinephrine-mediated activation of α2-receptors on presynaptic sympathetic nerve terminals is an example of a mechanism of what type of feedback?

A

Negative feedback

88
Q

Name four direct cholinergic agonists.

A

Bethanechol, carbachol, pilocarpine, methacholine

89
Q

What is the clinical application of bethanechol?

A

Treatment of postoperative and neurogenic ileus and urinary retention (remember: Beth Anne, call (bethanechol) me if you want to activate your Bowels and Bladder)

90
Q

What is the mechanism of action of bethanechol?

A

Bethanechol is a direct cholinergic agonist resistant to acetylcholinesterase that works on receptors in the bowel and bladder

91
Q

What two direct agonist cholinomimetic drugs can be used to treat glaucoma?

A

Carbachol and pilocarpine

92
Q

Carbachol and pilocarpine are effective for the treatment of open-angle glaucoma because they activate what muscle?

A

The ciliary muscle of the eye

93
Q

What is a methacholine challenge test?

A

A test in which methacholine is inhaled to stimulate muscarinic receptors and induce bronchoconstriction to diagnose asthma

94
Q

Pilocarpine is effective for the treatment of narrow-angle glaucoma because it activates what muscle?

A

The pupillary sphincter

95
Q

True or False? Pilocarpine is susceptible to acetylcholinesterase.

A

FALSE

pilocarpine is resistant to acetylcholinesterase

96
Q

Name five indirect cholinergic agonists.

A

Neostigmine, pyridostigmine, edrophonium, physostigmine, echothiophate

97
Q

What are the clinical indications for use of neostigmine?

A

The treatment of postoperative and neurogenic ileus

98
Q

True or False? The treatment of myasthenia gravis is a clinical application of pyridostigmine.

A

TRUE

99
Q

Which anticholinesterase is used to diagnose myasthenia gravis? Why?

A

Edrophonium; the effects last for minutes and if weakness is transiently reversed it is diagnostic of myasthenia gravis

100
Q

True or False? The treatment of glaucoma is a clinical application of physostigmine.

A

TRUE

(remember: "PHYS is for the EYES")

101
Q

Which pharmacologic agent is used to treat atropine overdose?

A

Physostigmine, because it crosses the blood-brain barrier and is able to reverse central nervous system as well as peripheral nervous system effects

102
Q

What is the clinical indication for use of echothiophate?

A

The treatment of glaucoma

103
Q

Indirect cholinergic agonists increase endogenous acetylcholine by inhibiting what enzyme?

A

Acetylcholinesterase

104
Q

Why is pyridostigmine used to treat myasthenia gravis?

A

It increases the amount of acetylcholine in the neuromuscular synapse, thereby increasing muscle strength

105
Q

What effect does neostigmine have on the central nervous system?

A

None; it does not penetrate the blood-brain barrier (remember: NEO CNS = NO CNS)

106
Q

What is the clinical application and mechanism of action of topical atropine, homatropine, and tropicamide?

A

These drugs antagonize muscarinic receptors in the eye to produce mydriasis and cycloplegia

107
Q

What is the mechanism and clinical application for benztropine?

A

It is a muscarinic antagonist used to reduce symptoms of Parkinson's disease

108
Q

What is the mechanism and clinical application for scopolamine?

A

It is a muscarinic antagonist used to treat motion sickness

109
Q

What is the mechanism and clinical application for ipratropium?

A

It is a muscarinic antagonist used to treat asthma and chronic obstructive pulmonary disease (remember: I PRAY I can breathe soon!)

110
Q

What is the mechanism and clinical application for methscopolamine?

A

It is a muscarinic antagonist used to treat peptic ulcers

111
Q

What is the mechanism and clinical application for oxybutynin?

A

It is a muscarinic antagonist used to reduce urgency in mild cystitis and reduce bladder spasms

112
Q

What is the mechanism and clinical application for glycopyrrolate?

A

It is a muscarinic antagonist used to reduce urgency in mild cystitis and reduce bladder spasms

113
Q

What is the mechanism and clinical application for pirenzepine?

A

It is a muscarinic antagonist used to treat peptic ulcers

114
Q

What is the mechanism and clinical application for propantheline?

A

It is a muscarinic antagonist used to treat peptic ulcers

115
Q

Which muscarinic antagonist can be used to reduce urgency in patients with mild cystitis?

A

Oxybutynin (also glycopyrrolate)

116
Q

Which muscarinic antagonist is most commonly used to treat motion sickness?

A

Scopolamine

117
Q

Which muscarinic antagonist can be used to treat bladder spasms?

A

Oxybutynin (also glycopyrrolate)

118
Q

You recently prescribed haloperidol to your patient to treat his schizophrenia, but he has since developed Parkinson's-like motor adverse effects. What drug could you add to his regimen to treat this?

A

Benztropine

119
Q

Atropine is used for therapeutic effect in which four organ systems?

A

Eyes, gastrointestinal system, respiratory system, urinary system

120
Q

What are the two effects of atropine on the eye?

A

Pupil dilation, cycloplegia

121
Q

What is the effect of atropine on the airway mucosa?

A

It decreases secretions

122
Q

What is the effect of atropine on the stomach?

A

It decreases acid secretion

123
Q

What is the effect of atropine on gastrointestinal motility?

A

It decreases motility

124
Q

What is the effect of atropine on the bladder in a patient with cystitis?

A

It decreases urgency

125
Q

(A) represents what neurotransmitter and receptor type?

A

Acetylcholine neurotransmitter; nicotinic receptor

126
Q

Part of the sympathetic NS, sweat glands and adrenal medulla are innervated by which neurotransmitter/receptor group, marked (A) and (B)?

A

(A) acetylcholine neurotransmitter/muscarinic receptor; (B) nicotinic neurotransmitter/muscarinic receptor

127
Q

A patient affected by botulinum toxin will be affected at which neurotransmitter/receptor group(s)?

A

Botulinum toxin affects all neurotransmitter/receptor groups that have acetylcholine as the neurotransmitter