Lectures 6, 7, & 8

Question 1

How does LTP inducing stimulus increase trapping of AMPA receptors?

Answer 1

CAMKII, Stargazing, and PSD-95

Question 2

What does PSD-95 do to increase AMPA in the synapse?

Answer 2

Form potential slots for trapping AMPA receptors diffusing through the PSD

Question 3

How does CAMKII increase AMPA receptor number in the synapse?

Answer 3

Phosphorylation stargazin from the membrane to facilitate binding to PSD-95

Question 4

What does stargazin do to increase AMPA receptor number in the synapse?

Answer 4

Binding of stargazin to PSD-95 traps more AMPA receptors

Question 5

How do endosomes get activated?

Answer 5

Calcium

Question 6

What does inhibiting the endosomes in the intracellular pool do?

Answer 6

Reduce LTP by a lot

Question 7

How does the actin cytoskeleton get degraded?

Answer 7

Ca2+ coming in activates a signaling cascade to degrade the actin skeleton

Question 8

What happens if you introduce a LFS within 10 minutes of a TBS stimulation?

Answer 8

LTP will be induced but not sustained

Question 9

To have LTP endure for more than 30 minutes, additional processes must be engaged to create a dendritic spine environment that will….

Answer 9

Prevent endocytotic processes that remove AMPA from the PSD & ensure delivery of a steady supply of synaptic proteins

Question 10

What is the stabilization phase?

Answer 10

During the 30 min period after LTP induction that involves remodeling of the dendritic spines

Question 11

Does spine size have a relation with AMPA receptor number in the PSD?

Answer 11

Yes! Large spines can live for days in living animals

Question 12

Changes in dendritic spine density, size and plasticity underlie ___ ___ due to age

Answer 12

Cognitive changes

Question 13

What are the two states actin exists in?

Answer 13

F-actin and G-actin

Question 14

What is the polymerized version of Actin called?

Answer 14

F-Actin

Question 15

What is the monomer version of Actin called?

Answer 15

G-actin

Question 16

When phosphorylated, what does cofilin do?

Answer 16

Help F-actin build polymers

Question 17

What does cofilin do when unphosphorylated?

Answer 17

Severs and depolymerized actin filaments

Question 18

What happens when you apply a drug that prevents actin polymerization before TBS?

Answer 18

LTP is induced but rapidly decays

Question 19

What phosphorylates cofilin?

Answer 19

LIMK

Question 20

What happens if a drug that prevents actin polymerization is applied 15 minutes after TBS?

Answer 20

LTP Is maintained

Question 21

What returns cofilin back to its unphosphorylated stated?

Answer 21

Slingshot

Question 22

How are actin filaments connected when not in LTP?

Answer 22

In a meshlike network in the spine head held by inactive CAMKII

Question 23

What does the neck of the synapse contain?

Answer 23

Bundles of F-actin held together by an inactive CaMKII complex

Question 24

What happens when CaMKII is activated and detached from F-actin?

Answer 24

Proteins sever the strands into shorter strands and cofilin depolymerized F-actin and prevents them from rejoining

Question 25

What happens once cofilin is phosphorylated?

Answer 25

Cofilin stops depolymerizing and then the new small F-actin strands rapidly polymerize

Question 26

How long do the 2-phases of disassembling to rebuilding take?

Answer 26

~30 minutes

Question 27

What do Cell Adhesion Molecules do to stabilize LTP?

Answer 27

They are proteins that are located on the cell surface and bind with other cells with the ECM

Question 28

What are the two important cell-adhesion molecules?

Answer 28

Integrin receptors and N-Cadherins

Question 29

What do integrin receptors do?

Answer 29

Connect the ECM to the actin cytoskeleton Influx of Ca2+ and induced signal cascades increases integrin in PSD

Question 30

What do N-Cadherins do?

Answer 30

Facilitate the coupling of pre and post synaptic regions Increased synaptic activity makes them cluster and help keep the pre and post regions tightly coupled

Question 31

What are the 3 main phases of stabilization of LTP?

Answer 31

Actin severing, rapid polymerization, cell adhesion

Question 32

The generation of new proteins is important to the ____ phase of the trace

Answer 32

Consolidation

Question 33

What does treatment with a protein synthesis inhibitor prior to a TBS do to LTP and induction?

Answer 33

LTP induced but does not last

Question 34

Long lasting LTP depends on both what?

Answer 34

Local and activity induced signaling of the genome

Question 35

How does genomic signaling work?

Answer 35

Signaling molecules activated by LTP can lead to new mRNA that can sustain LTP Signaling molecules enter nucleus and phosphorylated transcription factors that interact with DNA to create new mRNA and proteins to modify synapses

Question 36

What are the two ways signaling molecules can reach the nucleus?

Answer 36

Synapse to nucleus Soma to nucleus

Question 37

Describe the synapse to nucleus signaling pathway

Answer 37

- stim of post synaptic neuron activates secondary messengers - second messengers activate protein kinases which translocate to the nucleus - phosphorylation of CREB protein - CREB initiation transcription of proteins important to synapse

Question 38

Describe Soma to Nucleus signaling

Answer 38

- APs from LTP induction open vdCCs on membrane of soma - calcium can signal a number of important events - within and outside the nucleus leads to CREB phosphorylation - phosphorylation of CREB protein leads to transcription of important proteins to synapse