Neurobio Test2: Recitation 6

Question 1

What is SEP

Answer 1

pH sensitive dye

Question 2

How is SEP used in the study?

Answer 2

N-terminus of glutamate receptors are tagged. If they move from low pH of endosomes, to neutral pH of neuron surface, dye lights up

Question 3

How do authors mimic LTP?

Answer 3

Electrode stimulation of CA1 mimicking epilepsy

Question 4

What is APV

Answer 4

Drug that blocks NMDA receptors

Question 5

What is APV used to demonstrate

Answer 5

Enlargement of dendritic spines no longer induced with APV during LTP-level stimulation. NMDARs must be needed for enlargement

Question 6

Increase in receptors due to lateral migration of endocytosis? How do you know?

Answer 6

No significant change in number dendritic receptors before and after LTP - must be exocytosis

Question 7

Order of events: more AMPA receptors at spine, enlargement of spine

Answer 7

Spine enlarges first

Question 8

Is volume change of spines proportional to initial size?

Answer 8

No. End up at same volume.

Question 9

Presynaptic: CA3 or CA1

Answer 9

CA3

Question 10

CNQX

Answer 10

antagonist of AMPA

Question 11

How do we know receptors dont just diffuse and follow changes in surface area?

Answer 11

different subunits have different response to LTP

Question 12

How do we know fluorescence of pH-sensitive dye was not due to localization caused by fluoruophore?

Answer 12

Greater fluorescence was observed on edges of dendrites compared to center.

Question 13

Authors developed new method of inducing LTP involving bath application because

Answer 13

They needed to reliably stimulate a large number of neurons terminating at the synapses in their field of view

Question 14

How was the LTP protocol (chemLTP) developed for the study different than a seizure protocol?

Answer 14

1. removal of bath prevented spontaneous bursts
2. fully sensitive to APV
3. No spine loss or dendritic death
4. chemLTP drives GluR1 into synapses

Question 15

The fact that the spine enlarges before AMPA accumulates demonstrates:

Answer 15

existence of multiple distinct mechanisms during LTP

Question 16

Which receptors have the highest spine enrichment value?

Answer 16

NMDA

Question 17

Enrichment value

Answer 17

How much of the molecule is found within something else, such as the spine, plasma membrane, etc

Question 18

Rectification value

Answer 18

(EPSC amplitudes evoked at -60mV)/(EPSC amplitudes evoked at 40mV)

Question 19

What does rectification value show?

Answer 19

At 40mV, outward AMPA currents depend on GluR1 subunits. More of these means bigger denominator, which gives smaller rectification value.

Question 20

After ChemLTP, what happened to rectification value? This demonstrates:

Answer 20

Decreased.

AMPA with only GluR1 subunits were incorporated into synapses.