Jorgensen Specific Values

Question 1

Size limit of cytoplasmic coupling

Answer 1

< 1000 Da

Question 2

Da size of Calcium ions

Answer 2

40 Da

Question 3

Da size of NT

Answer 3

~150 Da

Question 4

Da size of GFP

Answer 4

27 kDA, 2.5 nm

Question 5

speed of action potential in myelinated axon

Answer 5

150 mm / ms

Question 6

speed of action potential in unmyelinated axon

Answer 6

10 mm / ms

Question 7

length (in time) of synaptic delay

Answer 7

0.5 - 3.0 ms
(1 ms)

Question 8

velocity of action potential

Answer 8

~ 25 mm / ms
(60 mph)

Question 9

width (in time) of AP

Answer 9

1 ms

Question 10

range in widths of AP

Answer 10

100 us - 1 ms

Question 11

how long does it take NTs to diffuse across synaptic cleft?

Answer 11

1 us

Question 12

distance of synaptic cleft?

Answer 12

20 nm

Question 13

amount of time it would take NTs to diffuse across 1 mm axon?

Answer 13

30 mins

Question 14

[Na_in]

Answer 14

5 - 20 mM
(10 mM)

Question 15

[Na_ex]

Answer 15

130-160 mM
(140 mM)

Question 16

[K_in]

Answer 16

130-160 mM
(140 mM)

Question 17

[K_ex]

Answer 17

4-8 mM
(5 mM)

Question 18

[Ca_in]

Answer 18

.05 - 1 uM
(50nM)

Question 19

[Ca_ex]

Answer 19

1.2-4 mM
(2mM)

Question 20

length of synaptic delay

Answer 20

.5 - 3 ms
1 ms

Question 21

how long does vesicle fusion take?

Answer 21

150 us

Question 22

how long does diffusion across synaptic cleft take?

Answer 22

1-5 us
(cleft 20-50 nm)

Question 23

how long does it take LGIC to open?

Answer 23

150 us

Question 24

[calcium] required for NT release?

Answer 24

~ 25 uM

Question 25

length of synaptic bouton

Answer 25

1 um

Question 26

width of KcsA potassium channel

Answer 26

20 nm

Question 27

size of single protein

Answer 27

5 nm
300 AA

Question 28

size of protein complex

Answer 28

~12 nm

Question 29

distance across plasma membrane

Answer 29

4 nm

Question 30

Electrical Synapse Summary

Answer 30

1. direct coupling of cytoplasm (electrically-coupled, dye-coupled)
2. attenuates signal (100 mV action potential can be reduced to 1 mV current)
3. often short duration, (~width AP; linked to memb potential timecourse)
4. mimic the ionic conditions of the cell (excitatory or inhibitory)
5. bidirectional information flow (but some are rectifiyng),
6. some gated (for example, by changes in calcium, pH, lipid composition)
7. generally not plastic or modifiable

Question 31

quantal content equation

Answer 31

evoked responses / mini size = #SV/AP = quantal content

Question 32

NSF

Answer 32

N-ethylmaleimide sensitive factor. Named because the activity is blocked by the drug. eventually separates the SNARES

Question 33

SNAPs (a,b)

Answer 33

soluble NSF attachment proteins. Named based on discovery method (binds to NSF)

Question 34

SNARE

Answer 34

SNAP receptor. Named based on discovery of binding NSF via a/b SNAP

Question 35

V-SNARE

Answer 35

vesicle SNARE (R-SNARE). Transmembrane protein in the vesicle which confers specificity. Called ‘synaptobrevin’ or ‘VAMP’ at the synapse.

Question 36

T-SNARE

Answer 36

target membrane SNARE (Q-SNARE). Transmembrane protein in the target membrane which confers specificity. Called ‘syntaxin’ and ‘SNAP-25) at the synapse

Question 37

SNARE complex

Answer 37

ultra-stable trimeric complex composed of V-SNARE (synaptobrevin), T-SNAREs (syntaxin and SNAP-25)

Question 38

about how long does it take calcium channels to open in the presynaptic neuron?

Answer 38

300 us

Question 39

Kd for calcium

Answer 39

0.1 uM

Question 40

Calcium channels model

Answer 40

Question 41

Ca response to different APs

Answer 41

Question 42

calcium influx (and hence neurotransmitter release) is determined by:

Answer 42

(1) calcium channel kinetics
Kinetics of open state Ca channels
i. slow activation kinetics
ii. high temperature sensitivity (Q10 = 6 to 12)

(2) by driving force for calcium
predicted reversal potential (2mM external 50 nM internal) = +130 mV reported reversal potential for calcium = +40-7 mV (not +130 mV)
i. low driving force at peak Vm of action potential
ii. high driving force as Vm repolarizes

Question 43

calcium sensor

Answer 43

synaptotagmin

also required for fast vessicle fusion (accelerates but not essential)