Lecture 6 Flashcards Preview

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Flashcards in Lecture 6 Deck (91):
1

These increase neuronal surface for synaptic contact:

dendrites

2

Where do afferent axons synapse in CNS?

nerve cell bodies and dendrites

3

T or F? Input to neurons in the CNS is always excitatory.

F. either

4

Small protrusions off of dendrites:

spine

5

Is the shaft synapse excitatory, inhibitory, or either?

either

6

Is the spine synapse excitatory, inhibitory, or either?

only excitatory

7

Is the somatic synapse excitatory, inhibitory, or either?

mainly inhibitory

8

Is the axoaxonic synapse excitatory, inhibitory, or either?

inhibitory

9

This type of synapse is prevalent in CNS during development - less so in adult CNS:

Electrical

10

This type of synapse is the only mode of transmission bw cardia and smooth muscle cells:

electrical

11

What are electrical synapses found in mature neurons?

in interneuronal connections

12

The synaptic efficacy of this/these type(s) of synapse can be modulated;

chemical

13

A molecule must be under ____ Daltons to pass through a GAP jucntion:

1000

14

Coupling bw cell connected via GAP junctions is both:

electrical and metabolic

15

T or F? The CNS ECM in the synaptic clefts.

F. No ECM

16

Which are narrower, clefts of the NMJ or clefts of the CNS synapse?

CNS synapse (no ECM)

17

Which has a greater postsynaptic density, excitatory or inhibitor bouton?

excitatory

18

What anchors transmitter receptor and intracellular signaling machinery in excitatory synapse?

prominent postsynaptic density

19

This type of vesicle recycling is involved in high frequency firing:

Kiss-and-run fusion

20

2 types of vesicle recycling:

Kiss-and-run and fusion and collapse

21

Step in competence maturation of fusion vesicles:

docked, primed, cocked, armed

22

What is required for vesicle docking?

Ca binds to receptor and changes conformation

23

What is the fusion event mediated by?

snare proteins

24

This snare protein is on the vesicle membrane:

V-snare

25

This snare protein is on the target membrane:

T snare

26

These are targets of botulinum:

SNARE proteins

27

V-snare:

synaptobrevin

28

T-snare:

syntaxin and SNAP-25

29

Calcium sensor:

synaptotagmin

30

T or F? Once a vesicle is armed it can go either pathway, Kiss-and-run or fusion and collapse.

T

31

This type of vesicle recycling has a readily releasable pool:

Kiss-and-Run

32

What happens if SNARE proteins encounter botulin toxin?

fusion and exocytosis is prevented, blocking transmission

33

T or F? The whole vesicle is collapsed in both Kiss-and-run and fusion and collapse.

F. Not in Kiss-and-run

34

2 major classes of ion channels:

voltage and ion gated

35

Where does neurotransmitter bind in order for a channel to open?

to a receptor on the ion channel

36

Are "fast neurotransmitters" used with ligand-gated channels, voltage-gated channels, or either?

ligand-gated

37

Are "slow neurotransmitters" used with ligand-gated channels, voltage-gated channels, or either?

either

38

This type of neurotransmitter mediates synaptic transmission:

"fast neurotransmitters"

39

This type of neurotransmitter modulates synaptic transmission:

"slow neurotransmitters"

40

Do GPCRs act with "slow neurotransmitters" or "fast neurotransmitters?"

"slow neurotransmitters"

41

T or F? Ligand-gated ion channels are metabotropic.

F Ionotropic

42

Are GPCRs ionotropic or metabotropic?

metabotropic

43

What does the G-protein bind to once activated?

effector protein

44

This type of neurotransmitter can trigger a 2nd msg pathway and regulate phosphorylation:

"slow neurotransmitter"

45

2 major families of ligand-gated channels:

1. Glutamate receptors
2. GABA (inhibitory - CNS), ACh, Glycine (check)

46

Where are both the ligand binding domain and the C terminal located with ACh, GABA, and glycine receptors?

extracellularly

47

Where is the C terminal located in glutamate receptors?

intracellularly

48

How many subunits do GABA, ACh, and Glycine have?

5 subunits, each w/ 4 trans domains

49

How many subunits do glutamate receptors have?

4 subunits, each w/ 3 transmembrane domains

50

How many binding sites does the glutamate receptors have?

2, N terminal and 3rd and 4th exc loop

51

Where is the C terminal of the glutamate channel located?

intracellularly

52

What helps anchor the glutamate receptor, providing stability and mobility of the receptors?

proteins at postsynaptic site

53

Major NT in the CNS for excitation:

glutamate

54

Major NT at the NMJ:

ACh

55

What ends the action of NT(glutamate) in the CNS?

reuptake by terminals glial cells

56

Glutamatergic receptor types:

AMPA and NMDA (agonists)

57

T or F? AMPA and NMDA are both antagonists.

F. agonists

58

AMPA

1. permeable to Na and K
2. EPSP

59

NMDA

- permeable to Na, K and Ca
- complicated IC signaling
- EPSP
- blocked by Mg

60

Mg removal:

via depolarization

61

NMDA activation:

- presynaptic activation (release T)
- postsynaptic activation (remove Mg)

62

glutamate receptors

- ionotropic: AMPAR and NMDAR, have intrinsic channels
- metabotropic: g-coupled

63

AMPAR:

fast transmission

64

NMDAR:

- coincidence detector
- regulate synaptic plasticity
- key player in learning

65

glycine:

- co-agonist for NMDA to open channel fully
- increase conductance

66

PCP:

- antagonist for NMDA receptor
- binding site

67

Hebb's rule:

learning and memory depend on neurons modifications

68

excitotoxicity:

excessive inflow of Ca through NMDAR channels

69

glutamate pathway:

released -> bind at postsynaptic -> channels activated -> Na/K flux -> uptaken by excitatory AA transporters on glial cells -> becomes glutamine -> back to nerve terminal -> conversion

70

EAAT:

uptakes 90% of glutamate

71

GABA:

inhibitory in CNS

72

GABA:

termination reuptake by terminals and glial cells

73

glycinergic receptors

- postsynaptic in spinal cord and brain
- antagonist

74

GABAergic receptors

- postsynaptic in brain
- ionotropic
- antagonist

75

antagonist

block inhibitory signal -> potential very - -> hyperpolarization

76

GABA receptors binding sites

- for GABA
- for steroids: modulators
- for barbiturates: anesthetics

77

glutamate receptors location (AMPAR, NMDAR)

- postsynaptic densities
- dendritic spines and shafts (distal)

78

GABA receptors location

- soma (AP trigger zone)
- proximal dendrites
- limited inhibitory transmission so better location

79

EPSP

due to Na influx

80

IPSP

due to Cl influx

81

motoneuron

- 1 cell body with many dendrites
- dendrites serve as input segments
- 1 axon = 1 output

82

motoneuron synapse distribution

- 80% on dendrites
- 20% on cell body

83

divergence of motoneuron axon branches

governed by size of motor unit

84

glutamergic input

excitatory

85

GABAergic input

inhibitory

86

ACh release

- excitatory
- control of contraction

87

Patella tendon reflex pathway

- stretch stimulus -> stretch receptor in extensor muscle -> afferent activated -> excitatory monosynaptic and inhibitory disynaptic activated

88

excitatory monosynaptic

- extensor contraction stimulated
- release glutamate
- EPSP, stimulate dorsal root

89

inhibitory disynaptic

- flexor contraction prevented
- interneuron innervates motorneuron
- release glycine
- IPSP, stimulate posterior root

90

5 subunit ligand-gated channel

- NAChR, GABA R
- inhibitory in CNS
- each subunit = 4 TM
- C terminal is EC

91

4 subunit ligand-gated channel

- glutamate R
- excitatory
- 3 TM with IC loop
- C terminal is IC