Synaptic Transmission Flashcards

1
Q

Some of these may be docked already without needed calcium to make them

A

Vesicles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

These are procured by the spontaneous release of the contents of one vesicle

A

Mini postsynaptic potentials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

This depends on internal resistance (ri) and membrane resistance (rm)

A

Length constant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

These are easier to study than CNS synapses

A

NMJ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

SLIDE 27

A

SLIDE 27

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

These synapses allow for the coordinate firing of cells or neurons

A

Electrical synapses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

These are similar to CNS synapses

A

NMJ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

There are thousands of these on every neuron

A

Channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Synapses that are evolutionarily old and present in many organisms

A

Electrical synapses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Faster response, ionotropic receptors

A

Ligand gated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Summation that occurs when many signals come down the same axon quickly

A

Temporal summation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Synapses between dendrites and dendrites

A

Dendrodendritic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How can glia enhance presynaptic function?

A

Create more NT release due to cholesterol from glial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

These synapses are usually inhibitory

A

Grays type 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What types of things can G-proteins activate?

A

G-protein activated ion channels and second messengers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

These can regulate synaptic development by creating silent but structurally normal synapses, enhanced presynaptic functions, and being postsynaptically active (functions)

A

Glia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What happens to voltage over a distance that can be shown in a formula?

A

It will dissipate over a distance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What does connexin make up and what does that make up?

A

Connexin makes up a connexon which makes up a gap junction (a connexon of two cells coming together to form one pore)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

These are fast, large, reliable synapses. They release a lot of vesicles (lots of NTs)

A

NMJ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Usually dendrites cant fire these

A

APs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What can happen to the downstream steps for some time after the G protein has been inactivated?

A

They can proceed for some time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What happens after the G protein has activated or inhibited downstream effectors?

A

It eventually hydrolyzes the GTP and returns to the inactive form, terminating the signaling. It goes back to inactive to wait for the next signal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Comparing miniature and evoked potentials can be used to decide how many of these are released

A

Vesicles (NTs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

These are not released at the active zone and have a lower time course (50 msec), they generally are released in response to higher Ca levels (granules are parked further back)

A

Peptide NTs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

There are present in all cells as basic amino acids used in protein synthesis, but are loaded into synaptic vesicles by specific vesicular transporters

A

Glycine and glutamate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

When a neuron has two NTs and releases them at the same time, they are in the same vesicle

A

Co-release

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Eventhough activation of GPCRs doesn’t immediately depolarize or hyperpolarize the cell, they can do this by acting through second messenger systems

A

Modulate signaling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What does ACh cause at negative membrane potentials (voltages)?

A

Inward current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

This depends on diameter and electrical properties of cytoplasm and is constant in a mature neuron

A

Internal resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

These are slower acting and are seen with amino acid, amine, and peptide NTs

A

GPCRs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What do axons often do at NMJs?

A

Spread out to create lots of surface area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

This depends on synaptic activity and how many ion channels are open

A

Membrane resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

These activate receptors and mimic the actions of NTs. Examples include nicotine

A

Agonists

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

These synapses are common in mammalian CNS, glia, cardiac muscle cells, smooth muscle, epithelial cells, liver cells

A

Electrical synapses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What are enzymes markers for in cells?

A

Markers for what NT the cell makes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Is the synapse empty and is it organized?

A

It is not empty and it is highly organized

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Synapses between axons and axons

A

Axoaxonic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What is contained in a secretory granule (dense-core vesicle)

A

Protein NTs (they show up darker on EM views of a synapse)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Synaptic vesicles contain a large number of these specific vesicle SNARES

A

v-SNARES

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

These are between motor neurons and muscle

A

Neuromuscular junction (NMJ)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

These block receptor activation. Examples are curare and cobra venom

A

Antagonists

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What happens to many NTs in the synapse to terminate signaling (happens to the vast majority of NTs)?

A

Taken up into the neuron or nearby glial cells (astrocytes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

These types of synapses occur due to symmetrical membrane thickness at synapse

A

Grays type 2, usually inhibitory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

This toxin inc ACh release

A

Black widow venom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What are synaptic vesicles bound to in the presynaptic cell?

A

Docking proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

We want this to be high for a longer length constant

A

Membrane resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

These produce opening of VG Ca channels producing large influx of Ca

A

APs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

When a neuron has two NTs and releases them at the same time, they are in two different vesicles

A

Co-transmission

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Only small molecules and ions can move through these

A

Gap junctions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Why can dendrites with Na, Ca, and K channels synapse further from the axon hillock?

A

They can generate APs because the depolarizing input is transmitted further. It doesn’t just diffuse, it gets replenished

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What does the I/V (current/voltage) curve of a non-voltage dependent channel look like?

A

It is a straight line (SLIDE 48)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What is the equilibrium potential of Cl?

A

-65 mV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

This is not empty and it contains extracellular matrix proteins which help organize the synapse and enzymes which can break down NTs

A

Synaptic cleft

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Dendrites cant fire APs but they can do this

A

Add current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

This part of the transmitter gated channel is usually closed until ligand binds, or is stabilized in the open state by an agonist

A

Pore (channel)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

these are recycled by endocytosis in multiple ways

A

Vesicle membranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Most of these are treated as electrically passive cables

A

Dendrites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

If inhibitory synapses are present between the site of input (on soma or most likely dendrites) and the axon hillock, opening of Cl channels can do this to the depolarization

A

Shunt or short circuit the depolarization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

What do various NTs have that is distinct for them?

A

Distinct synthetic pathways

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

These form a continuous channel pore that is open always and connects two cells

A

Gap junction channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

Discovered chemical synapses in 1921 and the first NT, vagusstoff (ACh)

A

Loewi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

These can vary in structure seen as differences in membrane thickness

A

Pre and postsynaptic sides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

This is synthesized from glutamate by glutamic acid decarboxylase and loaded into vesicles

A

GABA

64
Q

What do oval vesicles indicate?

A

Inhibitory NTs

65
Q

This part of a neuron integrates many signals acting though multiple receptors

A

Postsynaptic neuron

66
Q

What is the next most common way for NTs to be removed behind reuptake?

A

Degradation by enzymes

67
Q

This protein is essential for Ca sensing and release won’t occur without it

A

Synaptotagmin

68
Q

Opening of Na, K, and Ca channels on special dendrites allows the addition of current which allows the propagation of what

A

EPSPs

69
Q

What does binding of the ligand (NT) to the receptor produce in a GPCR?

A

A conformational change which activates the g protein

70
Q

What must happen to the NT in the cleft for signaling to stop?

A

It must be destroyed or removed

71
Q

We want this to be low for a longer length constant. Fatter axon = lower this

A

Internal resistance

72
Q

These types of synapses occur do to asymmetrical membrane thickness at synapse

A

Grays type 1, usually excitatory

73
Q

These synapses are usually excitatory

A

Grays type 1

74
Q

Summation that occurs when many signals come from different axons

A

Spatial summation

75
Q

What type of synapses are most synapses in the brain?

A

Chemical

76
Q

These block acetylcholinesterase and thus acetylcholine breakdown. This results I the over stimulation then paralysis. Nerve gas and some insecticides are examples

A

Organophosphates

77
Q

There are more than 100 of these

A

Different NT receptors

78
Q

How does the G protein stop signaling?

A

It eventually hydrolyzes the GTP and returns to the inactive form, terminating the signaling. It goes back to inactive to wait for the next signal

79
Q

Dendrites that have longer length constants are able to do this

A

Synapse further from the axon hillock

80
Q

This is the point when the flow of current is reversed (in to out) and thus the voltage changes (negative to positive)

A

Reversal potential

81
Q

The process in which multiple inputs are combined within one neuron to determine an output

A

Synaptic integration

82
Q

What can the same transmitter produce in different receptors?

A

Same NT can have different actions depending on the type of receptor (fast at ligand gated but slow at GPCRs)

83
Q

Studied motor neurons going to mucles

A

Katz

84
Q

These create a highly organized matrix presynaptically to be able to be released quickly

A

VAS (vesicle attachment sites)

85
Q

Due to gating Na, K, and Ca, these are excitatory and produce excitatory post synaptic potentials (EPSPs)

A

nicotinic ACh receptors

86
Q

Step in synaptic transmission that is putting NTs in vesicles or secretory granules in the case of peptides

A
  1. loading into vesicles
87
Q

These proteins form gap junctions

A

Connexin proteins

88
Q

Overall structure of these types of receptors are similar

A

Ligand gated

89
Q

This has to be active for shunting to occur

A

Inhibitory synapse

90
Q

Can single channel spontaneously open?

A

Yes they can and they can be recorded

91
Q

The brain performs billions of these ever second

A

Neural computations

92
Q

Slower response, metabotropic receptors

A

GPCRs

93
Q

What makes cells with gap junctions (electrical signaling) so effective?

A

The postsynaptic cell requires almost no input to match firing of the presynaptic cell that had to reach an AP

94
Q

These are large dense-core vesicles which are further from the terminus

A

Secretory granules

95
Q

What can blockage of the process of enzyme degrading NTs cause?

A

Death due to overstimulation

96
Q

This gives some idea how far away from the axon hillock depolarization can occur and still get an AP

A

Length constant

97
Q

How else can NTs get out of the synapse other than destruction or removal?

A

Diffuse away

98
Q

The amplitude of this is a multiple of mini amplitudes produced by the release of each vesicle

A

The amplitude of an EPSP

99
Q

Step in synaptic transmission that creates the NT. Each has own enzymes needed for synthesis. Some neurons make multiple and release together or separately

A
  1. synthesis of NTs
100
Q

This side of the chem synapse has densities which contain receptors and associated proteins

A

Postsynaptic side

101
Q

What can happen to receptors that are exposed to NTs for too long

A

They become desensitized, the NTs need to be removed or destroyed to maintain normal synaptic function

102
Q

SLIDE 29

A

SLIDE 29

103
Q

Much of what we know about synapses first was learned at these

A

NMJ

104
Q

Most of these are composed of 4-5 subunits, change conformation after the ligand binds, and the channel opens within microseconds

A

Transmitter gated channels

105
Q

These are often present at synapses and participate in regulation of signaling

A

Astrocytes

106
Q

Studied CNS synapses

A

Eccles

107
Q

These go all the way to the end of the axon while these dont

A

To end = synaptic vesicles

Not to end = secretory granules

108
Q

This interacts with a specific vSNARE and synaptic vesicle fusion and release occurs rapidly by exocytosis (0.2msec)

A

Calcium

109
Q

Single or multiple ones of these can be present at synapses

A

Active zones

110
Q

These are also known as metabotropic receptors

A

GPCRs

111
Q

Discovered electrical synapses in 1959

A

Furshpan and Potter

112
Q

The axon hillock must be depolarized to threshold to generate this

A

AP

113
Q

These are located on the membrane at the presynaptic terminus to interact with v-SNARES

A

t-SNARES

114
Q

This is the number of NT molecules in a vesicle (usually several thousand)

A

Quantum

115
Q

These are present in every cell

A

Amino acids

116
Q

These two interact to dock the vesicle to the presynaptic membrane

A

v-SNARES and t-SNARES

117
Q

Astrocytes release these in response to NTs to modulate the synapse

A

Gliotransmitters

118
Q

What do round vesicles indicate?

A

Excitatory NTs

119
Q

This side of the chemical synapse has active zones with docked vesicles and secretory granules (large dense-core vesicles) which are further from the terminus

A

Presynaptic side

120
Q

What do folds do at the NMJ?

A

Inc the surface area to inc how many vesicles there can be (more NTs)

121
Q

There are a finite number of these per vesicle referred to as the quantum

A

NTs

122
Q

These are presynaptic and often G-protein-linked receptors, and give feedback to the neuron releasing the NT

A

Autoreceptors

123
Q

Shunting the depolarization through Cl channels opening is a way of doing this

A

Regulating synaptic transmission by reducing excitement (EPSP)

124
Q

These are used to tell us what other ions the channel may be permeable to

A

Reversal potentials

125
Q

The model receptor for ligand gated receptors

A

Nicotinic ACh receptors

126
Q

These are needed in cells with vital functions and cells with needed synchronized firing

A

Gap junctions

127
Q

Does every cell only make one NT?

A

No, some neurons can make multiple NTs

128
Q

This toxin blocks NT release

A

Botulinum toxin

129
Q

Synapses between axons and dendrites

A

Axodendritic, axospinous

130
Q

These allow for cells to fire at the same rate

A

Gap junctions

131
Q

What does Ca interact with to release NTs?

A

tSNARES

132
Q

6 steps of synaptic transmission

A
  1. synthesis of NTs
  2. loading into vesicles
  3. release of vesicles
  4. NT binding to postsynaptic receptors
  5. electrical response
  6. removal or destruction of NT
133
Q

What is the length constant?

A

The value at which depolarization is 37% of its original value

134
Q

The only amino acid NT not also used for protein synthesis

A

GABA

135
Q

What are dendrites that are able to generate APs (add current not fire an AP) called (they contain Na, K, and Ca channels)

A

Excitable dendrites

136
Q

Modulation through GPCRs by second messengers can alter this and potentially change this

A

Alter synaptic transmission and potentially change signaling over along time

137
Q

In the CNS, this could be as little as one vesicle, 0.1 mV, which makes sense bc integration is needed for computational functions of a neuron

A

Quantal analysis of EPSPs

138
Q

Step in synaptic transmission that involves a response through gate channels or biochem response through GPCRs

A
  1. electrical response
139
Q

These channels aren’t as selective as VG channels, they are selective for cations or anions

A

Transmitter gated channels

140
Q

The number of channels that open depend on the quantity of these being released

A

NTs

141
Q

These are synthesized at axon terminals and loaded into vesicles there by specific vesicular transporters

A

Amine NTs

142
Q

These are bidirectional, making the cells electronically coupled, and allowing fast communication

A

Gap junctions

143
Q

There is a reserve pool of these away from the synapse incase they are needed

A

Vesicles

144
Q

What does ACh cause at positive membrane potentials (voltages)?

A

Outward current

145
Q

The use of drugs to study of effect neurotransmission. Has lead to the identification of the molecular details of many of these steps

A

Neuropharmacology

146
Q

How are vesicles docked?

A

Within specific, defined structures

147
Q

Discovered and named the synapse in 1897

A

Sherrington

148
Q

These are synthesized in the soma like other proteins and transported in secretory granules via the fast axonal transport mechanism

A

Peptide NTs

149
Q

These have a presynaptic and postsynaptic side with a 20-50 nm cleft

A

Chemical synapses

150
Q

These are the largest NTs

A

Peptide NTs

151
Q

These channels gate Na, K, Ca

A

ACh receptors

152
Q

SLIDE 67

A

SLIDE 67

153
Q

200 vesicles are rebased by an AP, resulting in a -40 mV depolarization that needs to work every time here (it is fast and reliable)

A

NMJ

154
Q

SLIDE 22

A

SLIDE 22

155
Q

What does the I/V (current/voltage) curve of a voltage dependent channel look like?

A

It has a curve followed by a straight line (SLIDE 48)

156
Q

What does a G protein do once it has been activated?

A

Activates or inhibits downstream effectors

157
Q

These are inhibitory and thus open Cl channels and produce inhibitory post synaptic potentials (IPSPs)

A

Glycine and GABA