Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

UVic BIOL 367 - Spring 2020 > MT - Neuronal Function (Part 4): Synaptic Transmission > Flashcards

MT - Neuronal Function (Part 4): Synaptic Transmission Flashcards

1
Q

What differentiates the structure of an electrical synapse from that of a chemical synapse?

A

Electrical: gap junctions join presynaptic and postsynaptic cells
Chemical: synaptic cleft between presynaptic and postsynaptic cells

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

What is the name given to the functional protein complexes in gap junctions? What kind of synapses are these present in?

A

In electrical synapses, the functional protein complexes are called connexins.

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

How do electrical synapses allow a signal to pass from the presynaptic to the postsynaptic cell?

A

By allowing the passage of ions through aqueous pores called connexins. This changes the membrane potential.

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

What differentiates the directionality of chemical synapses from electrical synapses?

A

Chemical: unidirectional
Electrical: bidirectional

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

How was the movement of solutes through an electrical synapse proved?

A

Injection of dye into the presynaptic cell diffueses and fills the postsynaptic cell.

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

How would you calculate the coupling coefficient of two cells joined at an electrical synapse?

A

From cell 1->cell 2, K= R2 / (R2+Rc)

-Where R2 is resistance of cell 2 and Rc is resistance of coupling.

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

What ion is required for chemical synaptic transmission and mediates release of neurotransmitter vesicles into the synaptic cleft?

A

Calcium!

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

How many calcium ions are needed to mediate the release of a single neurotransmitter vesicle?

A

4 (bind to synaptotagmin).

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

Who discovered the acetylcholine neurotransmitter? How?

A

Otto Loewi noticed that if you stimulate the vagus nerve of a frog it decreases heart rate. Moved the solution that the heart was in to another heart and observed the same thing!

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

What is the term used to refer to the smallest unit of neurotransmitter release?

A

“Quantal” release. Actually found before they knew that this was the amount of neurotransmitter contained in a vesicle.

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

In what part of the synapse are docked vesicles arranged prior to neurotransmitter release?

A

The “active zone”.

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

Are all chemical synapse active zones the same? Elaborate.

A

No, they can have various arrangements of Ca-channel colocalization around the vesicles.

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

What equation gives the mean size of postsynaptic response from a chemical synapse?

A

Response = # of available sites * prob. of release @ any site * response from 1 quanta. (PSR = n p q)

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

What protein in the membrane of synaptic vesicles binds calcium?

A

Synaptotagmin.

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

What 4 steps outline vesicle fusion at the presynaptic membrane?

A
  1. SNARE complexes form
  2. Synaptotagmin binds complex
  3. Ca2+ binds synaptotagmin
  4. Membrane fusion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the 2 membrane fusion proteins in the presynaptic vesicles?

A
  1. Synaptobrevin

2. Synaptotagmin

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

What are the 2 membrane fusion proteins in the presynaptic membrane?

A
  1. Syntaxin

2. SNAP-25

18
Q

What happens to vesicles following fusion with the presynaptic membrane and neurotransmitter release?

A

They are retrieved by endocytosis.

19
Q

What protein forms the coat around vesicles as they are being recovered from the presynaptic membrane post-fusion? How are these budded off?

A

Clathrin. Dynamin disconnects the vesicles from the membrane.

20
Q

Are GPCRs ionotropic or metabotropic?

A

Metabotropic (slow, non-ionic).

21
Q

What differentiates temporal summation from spatial summation?

A

Temporal: small, slightly staggered potentials cause net change of memb. pot.
Spatial: small potentials from various sites combine to cause net change of memb. pot.

22
Q

Are spatial summation and temporal summation distinct in-vivo?

A

No. They’re both really co-occurring all the time in the neurons.

23
Q

Describe the release of ACh at cholinergic synapses, starting from Acetyl CoA synthesis.

A
  1. Acetyl CoA produced by mitochondria
  2. Acetyl CoA -> ACh
  3. ACh packaged in vesicles
  4. ACh released into synapse
  5. ACh binds to receptor
  6. ACh -> choline + acetate
  7. Acetate diffuses, choline is recycled
24
Q

How many receptor subunits make up a muscle nicotinic ACh receptor? What are they?

A

Pentameric (5 subunits). 2 * α, β, γ/ε, δ.

25
Q

How many receptor subunits make up a neuronal nicotinic ACH receptor? What are they?

A

Pentameric (5 subunits). 1-5 * α, 1-3 * β.

26
Q

Where on the nicotinic ACh receptors do ligand(s) bind?

A

2 ligands bind to the α subunits to activate.

27
Q

What ion channels are fluxed through nicotinic ACh receptors?

A

Cations: Na+, K+, Ca2+.

28
Q

What is the reversal potential (equilibrium potential) for nicotinic ACh receptors?

A

~0mV.

29
Q

Are nicotinic ACh receptors excitatory or inhibitory?

A

Excitatory (depolarizes the membrane).

30
Q

What mechanism ensures that ACh signalling remains brief?

A

Acetylcholinesterase hydrolyzes ACh to choline and acetate.

31
Q

What are the 3 kinds of ionotropic glutamate receptors?

A
  1. AMPA receptors
  2. NMDA receptors
  3. Kainate receptors
32
Q

How many subunits are required to form an ionotropic glutamate receptor?

A

4.

33
Q

What do ionotropic glutamate receptors Kainate and AMPA require for opening? What ions do they flux?

A

They require only glutamate binding to open. Flux Na+ and K+.

34
Q

What does ionotropic glutamate NMDA receptor require for opening? What ions does it flux?

A

Requires membrane depolarization and glutamate/glycine binding to open. Flux Na+, K+, and Ca2+.

35
Q

What ion can NMDA receptors flux that AMPA and Kainate receptors can not?

A

Calcium.

36
Q

What is the reversal potential (equilibrium potential) for ionotropic glutamate receptors?

A

~0mV.

37
Q

Are ionotropic glutamate receptors excitatory or inhibitory?

A

Excitatory (depolarizes the membrane).

38
Q

How is glutamate removed from the synaptic cleft?

A

By glutamate transporters EATT on the presynaptic cell or on supporting glial cells.

39
Q

How many subunits are required to form a GABA receptor?

A

Pentameric (5 subunits).

40
Q

What is the reversal potential (equilibrium potential) for GABAa receptors?

A

~-99mV (the Nernst potential of Cl-).

41
Q

What ion do GABA receptors flux?

A

Cl-.

42
Q

Are GABAa receptors excitatory or inhibitory?

A

Inhibitory (hyperpolarize the membrane).

UVic BIOL 367 - Spring 2020 (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions