U6.1 INTRODUCTION TO CNS DRUGS

Question 1

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

Answer 1

T

Question 2

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

Answer 2

T

Question 3

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

Answer 3

T

Question 4

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.

Answer 4

brain and spinal cord

Question 5

Organization of the CNS

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

Answer 5

Neurons

Question 6

Organization of the CNS

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

Answer 6

Neuroglia

Question 7

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.

Answer 7

Blood-Brain Barrier

Question 8

Organization of the CNS : Neurons

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

Answer 8

Dendrite

Question 9

Organization of the CNS : Neurons

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

Answer 9

Axons

Question 10

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

Answer 10

Axon terminal

Question 11

Organization of the CNS : Neuroglia

most abundant cell in the brain and play homeostatic support roles

Answer 11

Astrocytes

Question 11

Organization of the CNS : Neuroglia

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

Answer 11

Oligodendrocytes

Question 12

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

Answer 12

Microglia

Question 13

Sodium Channel

Blocks channel from outside

Answer 13

Tetrodotoxin (TTX)

Question 14

Sodium Channel

Slows inactivation, shifts activation

Answer 14

Batrachotoxoin (BTX)

Question 14

Potassium channels

Blocks “small Ca-activated” K channel

Answer 14

Apamin

Question 15

Potassium channels

Blocks “big Ca-activated” K channel

Answer 15

Charybdotoxin

Question 16

Calcium channels

Blocks N-type channel

Answer 16

Omega conotoxin (ω-CTX-GVIA)

Question 17

Calcium channels

Blocks P-type channel

Answer 17

Agatoxin (ω-AGAIVA)

Question 18

Ligand-gated channel

Irreversible antagonist

Answer 18

α-Bungarotoxin

Question 19

Ligand-gated channel

Blocks channel

Answer 19

Picrotoxin

Question 20

Ligand-gated channel

Competitive antagonist

Answer 20

Strychnine

Question 21

Ligand-gated channel

Blocks channel

Answer 21

Philanthotoxin

Question 22

Ion Channel

Tetrodotoxin (TTX), Batrachotoxoin (BTX)

Answer 22

Voltage-gated, Sodium

Question 23

Ion Channel Apamin, Charybdotoxin

Answer 23

Voltage-gated, Potassium

Question 24

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

Answer 24

Voltage-gated, Calcium

Question 25

Ion Channel α-Bungarotoxin

Answer 25

Ligand-gated, Nicotinic Ach receptor

Question 26

Ion Channel Picrotoxin

Answer 26

Ligand-gated, GABAA receptor

Question 27

Ion Channel Strychnine

Answer 27

Ligand-gated, Glycine

Question 28

Ion Channel Philanthotoxin

Answer 28

Ligand-gated, AMPA

Question 29

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

Answer 29

1. Voltage-gated channels 2. Ligand-gated channels

Question 30

Ion Channels Responds to changes in membrane potential

Answer 30

Voltage-gated Ion Channels

Question 31

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

Answer 31

Voltage-gated Ion Channels

Question 32

Ion Channels Responsible for fast action potentials.

Answer 32

Voltage-gated Ion Channels

Question 33

Ion Channels Responsible for action potential propagation

Answer 33

Sodium Channels

Question 34

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

Answer 34

Voltage-gated Ion Channels

Question 35

2 Classes of Neurotransmitter Receptor

Answer 35

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

Question 36

Neurotransmitter Receptor Chemically-gated

Answer 36

Ligand-gated Ion Channels or Ionotropic Receptors

Question 37

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

Answer 37

Ligand-gated Ion Channels or Ionotropic Receptors

Question 38

Neurotransmitter Receptor Seven transmembrane G protein-coupled receptors (GPCRs)

Answer 38

Metabotropic Receptors

Question 39

Neurotransmitter Receptor Binding does not result in the direct gating of a channel

Answer 39

Metabotropic Receptors

Question 40

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

Answer 40

Metabotropic Receptors

Question 41

Membrane-Delimited Pathways

Answer 41

1. Potassium channels 2. Calcium channels

Question 42

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

Answer 42

T

Question 42

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

Answer 42

Metabotropic receptors

Question 43

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.

Answer 43

T

Question 44

predominate in the diffuse neuronal systems in the CNS

Answer 44

Metabotropic receptors

Question 45

The Synapse and Synaptic Potentials Types of receptor channel coupling in ligand-gated ion channels activation and inactivation

Answer 45

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.

Question 46

The Synapse and Synaptic Potentials Diffusible second messengers

Answer 46

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

Question 47

Role of the Ion current carried by the Channel Synapse : Communication

Answer 47

1. EPSPs 2. IPSPs

Question 48

Role of the Ion current carried by the Channel Depolarizing potential change

Answer 48

Excitatory Postsynaptic Potentials (EPSPs)

Question 49

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

Answer 49

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

Question 50

EPSPs __ Na+, __ K+, __ Ca2+

Answer 50

↑ Na+, ↓ K+, ↑ Ca2+

Question 51

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

Answer 51

T

Question 52

Role of the Ion current carried by the Channel Hyperpolarizing potential change

Answer 52

Inhibitory Postsynaptic Potentials (IPSPs)

Question 53

IPSPs Generated by

Answer 53

Opening of potassium or chloride channels.

Question 54

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

Answer 54

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

Question 55

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.

Answer 55

T

Question 56

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

Answer 56

F; direct interactions

Question 57

Sites and Mechanisms of Drug Action drugs exert their effect through direct interactions

Answer 57

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

Question 58

Sites and Mechanisms of Drug Action Most drugs exert their effect mainly at the ____.

Answer 58

synapses

Question 59

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

Answer 59

T

Question 60

Sites and Mechanisms of Drug Action Pre- and postsynaptic receptors for specific transmitters

Answer 60

Activate or Block

Question 61

Sites and Mechanisms of Drug Action Interfere with the action of second messengers

Answer 61

Activate or Block

Question 62

Sites and Mechanisms of Drug Action Inhibits synthesis of serotonin

Answer 62

Parachlorophenylalanine

Question 63

Sites and Mechanisms of Drug Action Inhibits storage of catecholamines

Answer 63

Reserpine

Question 64

Sites and Mechanisms of Drug Action Inhibits release of catecholamines

Answer 64

Amphetamine

Question 65

Sites and Mechanisms of Drug Action Inhibits degradation of acetylcholine

Answer 65

Anticholinesterase

Question 66

Sites and Mechanisms of Drug Action Can be depressed by blockade of transmitter synthesis or storage

Answer 66

Presynaptic Drugs

Question 67

Sites and Mechanisms of Drug Action The transmitter receptor provides the primary site of drug action

Answer 67

Postsynaptic Region

Question 68

Cellular Organization of the Brain Two types of neuronal system:

Answer 68

1. Hierarchical system 2. Diffused/Non-specific neuronal system

Question 69

Cellular Organization of the Brain Contains large myelinated, rapidly conducting fibers; pathways are clearly delineated.

Answer 69

Hierarchal System

Question 70

Cellular Organization of the Brain Control major sensory and motor functions

Answer 70

Hierarchal System

Question 71

Cellular Organization of the Brain Excitability of the CNS

Answer 71

Hierarchal System

Question 72

Cellular Organization of the Brain Major Excitatory Transmitters : Aspartate, Glutamate

Answer 72

Hierarchal System

Question 73

Cellular Organization of the Brain Small Inhibitory Interneurons Transmitters

Answer 73

Gamma amino butyric acid (GABA), Glycine

Question 74

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

Answer 74

Diffused / Non-Specific Neuronal System

Question 75

Diffused / Non-Specific Neuronal System Periodic enlargements that contain transmitter vesicles

Answer 75

Varicosities

Question 76

Diffused / Non-Specific Neuronal System Located in the axons

Answer 76

Varicosities

Question 77

Diffused / Non-Specific Neuronal System (Transmitters) NE, dopamine and serotonin

Answer 77

Noradrenergic Amines

Question 78

Diffused / Non-Specific Neuronal System (Transmitters) act on metabotropic receptors

Answer 78

Peptides

Question 79

Diffused / Non-Specific Neuronal System Noradrenergic cell bodies are found primarily in a compact cell group _________.

Answer 79

locus caeruleus

Question 80

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

Answer 80

Serotonin neurons

Question 81

Cellular Organization of the Brain Other diffusely projecting neurotransmitter pathways include the histamine and orexin systems

Answer 81

Diffused / Non-Specific Neuronal System