U6.1 INTRODUCTION TO CNS DRUGS Flashcards

1
Q

T/F Nearly all drugs with CNS effects act on specific receptors that modulate transmission.

A

T

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2
Q

T/F CNS drugs are among the most important tools for studying all aspects of CNS physiology.

A

T

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3
Q

T/F Unraveling the actions of drugs with known clinical efficacy led to the hypotheses regarding the mechanism of disease.

A

T

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4
Q

Organization of the CNS

The CNS is composed of the ____ nd _____ and is responsible for integrating sensory information and generating motor output and other behaviors needed to successfully interact with the environment and enhance species survival.

A

brain and spinal cord

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5
Q

Organization of the CNS

Electrically excitable cells that process and transmit information via an electrochemical process.

A

Neurons

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6
Q

Organization of the CNS

Large number of non-neuronal support cells, called glia, that perform a variety of essential functions in the CNS.

A

Neuroglia

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7
Q

Organization of the CNS

A protective functional separation of the
circulating blood from the extracellular fluid of the CNS that limits the penetration of substances, including drugs.

A

Blood-Brain Barrier

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8
Q

Organization of the CNS : Neurons

receive and integrate the input from other neurons and conduct this information to the cell body.

A

Dendrite

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9
Q

Organization of the CNS : Neurons

carry the output signal of a neuron from the cell body, sometimes over long distances

A

Axons

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10
Q

Organization of the CNS : Neurons

makes contact with other neurons at specialized junctions called synapses where neurotransmitter chemicals are released that interact with receptors on other neurons

A

Axon terminal

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11
Q

Organization of the CNS : Neuroglia

most abundant cell in the brain and play homeostatic support roles

A

Astrocytes

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11
Q

Organization of the CNS : Neuroglia

cells that wrap around the axons of projection neurons in the CNS forming the myelin sheath

A

Oligodendrocytes

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12
Q

Organization of the CNS : Neuroglia

specialized macrophages derived from the bone marrow that settle in the CNS and are the major immune defense system in the brain

A

Microglia

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13
Q

Sodium Channel

Blocks channel from outside

A

Tetrodotoxin (TTX)

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14
Q

Sodium Channel

Slows inactivation, shifts activation

A

Batrachotoxoin (BTX)

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14
Q

Potassium channels

Blocks “small Ca-activated” K channel

A

Apamin

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15
Q

Potassium channels

Blocks “big Ca-activated” K channel

A

Charybdotoxin

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16
Q

Calcium channels

Blocks N-type channel

A

Omega conotoxin (ω-CTX-GVIA)

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17
Q

Calcium channels

Blocks P-type channel

A

Agatoxin (ω-AGAIVA)

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18
Q

Ligand-gated channel

Irreversible antagonist

A

α-Bungarotoxin

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19
Q

Ligand-gated channel

Blocks channel

A

Picrotoxin

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20
Q

Ligand-gated channel

Competitive antagonist

A

Strychnine

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21
Q

Ligand-gated channel

Blocks channel

A

Philanthotoxin

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22
Q

Ion Channel

Tetrodotoxin (TTX), Batrachotoxoin (BTX)

A

Voltage-gated, Sodium

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23
Q

Ion Channel

Apamin, Charybdotoxin

A

Voltage-gated, Potassium

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24
Q

Ion Channel

Omega conotoxin (ω-CTX-GVIA), Agatoxin (ω-AGAIVA)

A

Voltage-gated, Calcium

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25
Q

Ion Channel

α-Bungarotoxin

A

Ligand-gated, Nicotinic Ach receptor

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26
Q

Ion Channel

Picrotoxin

A

Ligand-gated, GABAA receptor

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27
Q

Ion Channel

Strychnine

A

Ligand-gated, Glycine

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28
Q

Ion Channel

Philanthotoxin

A

Ligand-gated, AMPA

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29
Q

The nerve cells contain two types of channels defined on the basis of the mechanism controlling their gating (opening and closing) :

A
  1. Voltage-gated channels
  2. Ligand-gated channels
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30
Q

Ion Channels

Responds to changes in membrane potential

A

Voltage-gated Ion Channels

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31
Q

Ion Channels

Concentrated on the initial segment of the axons in
nerve cells.

A

Voltage-gated Ion Channels

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32
Q

Ion Channels

Responsible for fast action potentials.

A

Voltage-gated Ion Channels

33
Q

Ion Channels

Responsible for action potential propagation

A

Sodium Channels

34
Q

Ion Channels

Cell bodies and dendrites also have voltage-sensitive ion channels for potassium and calcium.

A

Voltage-gated Ion Channels

35
Q

2 Classes of Neurotransmitter Receptor

A
  1. Ligand-gated Ion Channels or Ionotropic Receptors
  2. Metabotropic Receptors
36
Q

Neurotransmitter Receptor

Chemically-gated

A

Ligand-gated Ion Channels or Ionotropic Receptors

37
Q

Neurotransmitter Receptor

Respond to chemical neurotransmitters (NTAs) that bind to receptor subunits of the channel.

A

Ligand-gated Ion Channels or Ionotropic Receptors

38
Q

Neurotransmitter Receptor

Seven transmembrane G protein-coupled receptors (GPCRs)

A

Metabotropic Receptors

39
Q

Neurotransmitter Receptor

Binding does not result in the direct gating of a channel

A

Metabotropic Receptors

40
Q

Neurotransmitter Receptor

Binding engages the G-protein that results in the production of second messengers that modulate the voltage-gated channels.

A

Metabotropic Receptors

41
Q

Membrane-Delimited Pathways

A
  1. Potassium channels
  2. Calcium channels
42
Q

T/F In neurons, activation of metabotropic neurotransmitter receptors often leads to the modulation of voltage-gated channels.

A

T

42
Q

Neurotransmitter Receptor

can also modulate voltage-gated channels less directly by the generation of diffusible second messengers.

A

Metabotropic receptors

43
Q

T/F An important consequence of the involvement of G proteins in receptor signaling is that, in contrast to the brief effect of ionotropic receptors, the effects of metabotropic receptor activation can last tens of seconds to minutes.

A

T

44
Q

predominate in the diffuse neuronal systems in the CNS

A

Metabotropic receptors

45
Q

The Synapse and Synaptic Potentials

Types of receptor channel coupling in ligand-gated ion channels activation and inactivation

A
  1. A receptor that acts directly on the channel protein.
  2. A receptor that is coupled to the ion channel through a G protein.
  3. A receptor coupled to a G protein that modulates the formation of diffusible second messengers.
46
Q

The Synapse and Synaptic Potentials

Diffusible second messengers

A

a. Cyclic adenosine monophosphate (cAMP)
b. Inositol trisphosphate (IP3)
c. Diacylglycerol (DAG)

47
Q

Role of the Ion current carried by the Channel

Synapse : Communication

A
  1. EPSPs
  2. IPSPs
48
Q

Role of the Ion current carried by the Channel

Depolarizing potential change

A

Excitatory Postsynaptic Potentials (EPSPs)

49
Q

Role of the Ion current carried by the Channel (EPSP)

Generated by

A
  1. Opening of sodium or calcium channels
  2. Closing of potassium channels in some synapses
50
Q

EPSPs

__ Na+, __ K+, __ Ca2+

A

↑ Na+, ↓ K+, ↑ Ca2+

51
Q

EPSPs

T/F As additional excitatory synapses are activated, there is a graded summation of the EPSPs to increase the size of the depolarization.

A

T

52
Q

Role of the Ion current carried by the Channel

Hyperpolarizing potential change

A

Inhibitory Postsynaptic Potentials (IPSPs)

53
Q

IPSPs

Generated by

A

Opening of potassium or chloride channels.

54
Q

IPSPs

__ K+, __ Cl- postsynaptic, __ Ca2+ presynaptic

A

↑ K+, ↑ Cl- postsynaptic, ↓ Ca2+ presynaptic

55
Q

IPSPs

T/F When an inhibitory pathway is stimulated, the postsynaptic membrane is hyperpolarized owing to the selective opening of chloride channels, producing an IPSP.

A

T

56
Q

Sites and Mechanisms of Drug Action

T/F Some drugs exert their effect through indirect interactions with molecular components of ion channels on axons.

A

F; direct interactions

57
Q

Sites and Mechanisms of Drug Action

drugs exert their effect through direct interactions

A
  1. Carbamazepine
  2. Phenytoin
  3. Local anesthetics and some drugs used for
    general anesthesia
58
Q

Sites and Mechanisms of Drug Action

Most drugs exert their effect mainly at the ____.

A

synapses

59
Q

Sites and Mechanisms of Drug Action

T/F Drugs may act presynaptically to alter synthesis, storage, release, reuptake & metabolism of transmitter chemicals.

A

T

60
Q

Sites and Mechanisms of Drug Action

Pre- and postsynaptic receptors for specific transmitters

A

Activate or Block

61
Q

Sites and Mechanisms of Drug Action

Interfere with the action of second messengers

A

Activate or Block

62
Q

Sites and Mechanisms of Drug Action

Inhibits synthesis of serotonin

A

Parachlorophenylalanine

63
Q

Sites and Mechanisms of Drug Action

Inhibits storage of catecholamines

A

Reserpine

64
Q

Sites and Mechanisms of Drug Action

Inhibits release of catecholamines

A

Amphetamine

65
Q

Sites and Mechanisms of Drug Action

Inhibits degradation of acetylcholine

A

Anticholinesterase

66
Q

Sites and Mechanisms of Drug Action

Can be depressed by blockade of transmitter synthesis or storage

A

Presynaptic Drugs

67
Q

Sites and Mechanisms of Drug Action

The transmitter receptor provides the primary site of drug action

A

Postsynaptic Region

68
Q

Cellular Organization of the Brain

Two types of neuronal system:

A
  1. Hierarchical system
  2. Diffused/Non-specific neuronal system
69
Q

Cellular Organization of the Brain

Contains large myelinated, rapidly conducting fibers; pathways are clearly delineated.

A

Hierarchal System

70
Q

Cellular Organization of the Brain

Control major sensory and motor functions

A

Hierarchal System

71
Q

Cellular Organization of the Brain

Excitability of the CNS

A

Hierarchal System

72
Q

Cellular Organization of the Brain

Major Excitatory Transmitters : Aspartate, Glutamate

A

Hierarchal System

73
Q

Cellular Organization of the Brain

Small Inhibitory Interneurons Transmitters

A

Gamma amino butyric acid (GABA), Glycine

74
Q

Cellular Organization of the Brain

Broadly distributed, with single cells frequently sending processes to many different parts of the brain-tangential

A

Diffused / Non-Specific Neuronal System

75
Q

Diffused / Non-Specific Neuronal System

Periodic enlargements that contain transmitter vesicles

A

Varicosities

76
Q

Diffused / Non-Specific Neuronal System

Located in the axons

A

Varicosities

77
Q

Diffused / Non-Specific Neuronal System (Transmitters)

NE, dopamine and serotonin

A

Noradrenergic Amines

78
Q

Diffused / Non-Specific Neuronal System (Transmitters)

act on metabotropic receptors

A

Peptides

79
Q

Diffused / Non-Specific Neuronal System

Noradrenergic cell bodies are found primarily in a compact cell group _________.

A

locus caeruleus

80
Q

Diffused / Non-Specific Neuronal System

found in the midline raphe nuclei in the forebrain and send extraordinarily divergent projections to nearly all regions of the CNS

A

Serotonin neurons

81
Q

Cellular Organization of the Brain

Other diffusely projecting neurotransmitter pathways include the histamine and orexin systems

A

Diffused / Non-Specific Neuronal System