Transmission Flashcards Preview

Neuroscience Exam 1 > Transmission > Flashcards

Flashcards in Transmission Deck (84)
Loading flashcards...
1

Presynaptic modulation

One neuron/synapse can alter the synaptic strength (membrane potential) or another synapse
Excitatory or inhibitory

2

Synaptic convergence

many synaptic terminals can synapse on a single cell

3

Synthesis of a NT occurs where

in terminal or cell body

4

chemical synapse

Uses neurotransmitter
Membranes NOT connected
Synaptic cleft

5

What are the 4 biochemical steps in synaptic transmission?

1. synthesis
2. storage and release
3. binding
4. removal

6

Which type of synapse has cytoplasmic continuity

electrical

7

Potentiation synaptic pasticity

Post synaptic potential becomes greater
Greater amounts of NT released

8

Spider toxin

blocks voltage gated Ca channels

9

What is the direction of transmission for chemical synapses?

1D

10

Axodendritic synapse

Axon synapses on a dendrite

11

distance between cell membranes in electrical synapses

2-4 nm

12

Where is acetylcholine made

terminal

13

Lingand gated ion channels employ what kind of receptor?

ionotropic

14

Where are synapses located?

Dendrites
Axons
Cell bodies

15

What is the synaptic delay in chemical synapses

Fast - .3 ms
slow - several ms

16

Synaptic divergence

One synaptic terminal can make contact with multiple post synaptic cells

17

What are the 3 methods of removal of NTs from a synapse after it's been released into the cleft?

1. diffusion
2. reuptake into presynaptic cell via transporters
3. enzymatic degradation

18

Ionotropic receptors

Direct coupling between NT and ion channel - receptor on the ion channel
NT binds and causes conformational change
FAST synaptic transmission

19

electrical synapse

Direct coupling between the two membranes - physically connected via ion channels
Direct passing of ionic current

20

How is acetylcholine synthesized

in terminal
Choline + acetyl CoA
Enzyme: cholineacetyltransferase

21

What is the synaptic delay in electrical synapses

none

22

Excitatory post synaptic potential

Depolarization - voltage increases

23

Multiple action potentials cause the release of NT from _____

large dense core vesicles

24

inhibitory post synaptic potentials

hyperpolarization - voltage decreases

25

What are the steps in G protein activation

1. Rest - no NT bound, binds GDP
2. NT binds to its receptor = conformational change in G protein
3. GDP replaced by GTP

26

Where in the synaptic cleft do vesicles release their contents?

active zone

27

Where do we find acetylcholine in the body?

muscles

28

Which kind of vesicles are associated with slow synaptic transmission?

Large dense core vesicles

29

Scorpion toxin

Blocks Na channels

30

What provides energy to G protein so it can move around to the interior of the cell

GTP

31

Quantal release

All-or-none release of NT from a vesicle

32

Tetrodotoxin (TXX)

Blocks voltage gated Na channels
Can't have action potential

33

G protein (Guanine Nucleotide Binding Protein)

Heterotrimer - 3 subunits (alpha, beta, gamma)
20+ types
alpha subunit contains guanine nucleotide binding site

34

What specific channels are mediated by activation of metabotropic receptors?

1. opening/closing voltage gated ion channels when membrane potential at rest (K channels)
2. voltage gated Ca channels
3. ligand gated ion channels - increase the time the channel is open/closed

35

distance between cell membranes in a chemical synapse

30-50 nm

36

Synaptic transmission

transfer of information from one neuron to another cell
Changes in membrane potential

37

Alpha-bungarotoxin

Snakes
Blocks nicotinic acetylcholine receptors

38

What kind of cell-to-cell connection is used in an electrical synapse?

Gap junction

39

What are the 4 criteria for a neurotransmitter?

1. made in neuron from which it is released
2. present in presynaptic terminal
3. exogenous application (natural effect - if NT is applied artificially it yeilds the same result)
4. mechanism for removal of NT

40

synaptic efficacy can be changed by other synapses via

pre synaptic facilication
pre synaptic inhibition

41

All G proteins share a common mechanism for ___

activation

42

Describe the steps of the synaptic transmission process in a chemical synapse

1. Action potential changes the membrane potential of the pre-synaptic neuron
2. Ca channels open
3. Ca influx into pre-synaptic cell
4. Vesicles move to membrane and release NT into cleft
5. NT bind to post-synaptic receptors
6. Changes membrane potential of post synaptic neuron

43

Effect of morphine

Blocks voltage gated Ca channels = decrease NT release = less excitability of post synaptic cell

44

Metabotropic receptors

G protein coupled receptors
Slow transmission
Large dense core vesicles
7 subunits

45

How is acetylcholine removed from the synaptic cleft after release? products?

Enzymatic degradation via cholinesterase
Products: choline, acetic acid

46

Temporal summation

summate over time

47

Large dense core vesicles

Contain NT that is synthesized in the cell body
Slow synaptic transmission

48

Gary's type I synapse

Excitatory
WIDE synaptic cleft (>30 nm)

49

What is the difference in permeability between ligand gated and voltage gated ion channels

Voltage - allow one type of ion to pass
Ligand gated - permeable to all

50

Inhibitory synapses have ligand gated ion channels that bind ______ and are permeable to ______

GABA, glycine
Cl

51

Synaptic cleft

The space between the two membranes of a chemical synapse

52

Metabotropic receptors

Indirect coupling between receptor and ion channel (G protein coupled receptor)
SLOW synaptic transmission

53

What are the 2 kinds of post synaptic potentials?

exitatory
inhibitory

54

What is the difference in regenerative capacity between ligand gated and voltage gated ion channels? (how are more channels activated)

Voltage - change in membrane potential
ligand gated - requires more NT

55

Post-synaptic potentials

changes in membrane potential

56

What kind of vesicle is associated with fast synaptic transmission?

small synaptic vesicles

57

Ligand gated ion channels

Ionotropic receptors - fast synaptic transmission
Binds NT in small synaptic vesicles
5 subunits

58

Receptors

component of the neuron (protein) that binds the NT and results in change in membrane potential

59

Quanta

amount of transmitter in one synaptic vesicle

60

Which is the most critical step of a chemical synapse transmission?

Ca moving into presynaptic terminal

61

synapse

specialized structure for the transfer of information

62

Can a cell recieve excitatory and inhibitory post synaptic potentials?

Yes - summate together for a net change in membrane potential

63

Conotoxins

Cone snails
Blocks acetylcholine (nicotinic) receptors in periphery
Causes paralysis
Can block Na, Ca, K channels

64

Depression synaptic plasticity

post synaptic potential weakens
Reduce amount of NT released

65

What are the 2 kinds of synaptic vesicles in chemical synapses?

small
large dense core

66

Which NT is released at a neuromusclular junction?

acetylcholine

67

A single action potential causes the release of NT from _____

small synaptic vesicles

68

Presynaptic inhibition on a specific terminal results in...

little IPSP across neuron except in specific terminal
Diminishes effect of only some excitatory synapses

69

What are the 2 methods that synapses can change their own efficacy? (synaptic plasticity)

potentiation
depression

70

What are they 2 types of synapse

electrical
chemical

71

Lambert Eaton Myasthenia Syndrome

Disorder of neuromuscular jxn
Muscle weakness
Autoimmune
Antibodies are made for voltage gated calcium channels - blocks entry of Ca into presynaptic neuron

72

Myasthenia gravis

neuromuscular jxn disorder
autoimmune
Antibodies made against acetylcholine receptors (nicotinic receptors)

73

Excitatory synapses have ligand gated ion channels that bind ______ and are permeable to _____

Acetylcholine, glutamate
Na, K, Ca

74

Neurotransmitter

small molecule released from the presynaptic membrane and interacts with receptors on post synaptic membrane triggering a change in membrane potential

75

Function of metabotropic receptors

Link NT receptors to effect molecules (enzymes)
Inside the cell - causes changes in ion channel activity - leading to changed in membrane potential

76

Gary's type II synapse

Inhibitory
Smaller cleft (<30 nm)

77

Flow of signals in electrical synapses are ______

bidirectional

78

In a standard inhibitory synapse, the inhibition occurs at the cell body. This causes...

Inhibitory PSP in all post synaptic neurons (in cell with multiple axons)
Diminishes the effect of all excitatory synapses on same neuron

79

axosomatic synapse

axon synapses on cell body (soma)

80

Small synaptic vesicles

Contain NT that is synthesized in the terminal
Used for fast synaptic transmission

81

Botulism toxin

Disorder of neuromuscular jxn
Toxin gets into terminal and interferes with proteins involved in the docking of vesicles

82

spatial summation

summate over entire cell

83

axoaxonic synapse

Axon synapses on another axon

84

Synaptic plasticity

Synapse strength (change in post synaptic potential) can be changed
Synapses can change their own synapse strength ON THEIR OWN