Lectures 6, 7, & 8 Flashcards

1
Q

How does LTP inducing stimulus increase trapping of AMPA receptors?

A

CAMKII, Stargazing, and PSD-95

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2
Q

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

A

Form potential slots for trapping AMPA receptors diffusing through the PSD

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3
Q

How does CAMKII increase AMPA receptor number in the synapse?

A

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

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4
Q

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

A

Binding of stargazin to PSD-95 traps more AMPA receptors

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5
Q

How do endosomes get activated?

A

Calcium

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6
Q

What does inhibiting the endosomes in the intracellular pool do?

A

Reduce LTP by a lot

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7
Q

How does the actin cytoskeleton get degraded?

A

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

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8
Q

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

A

LTP will be induced but not sustained

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9
Q

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

A

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

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10
Q

What is the stabilization phase?

A

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

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11
Q

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

A

Yes! Large spines can live for days in living animals

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12
Q

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

A

Cognitive changes

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13
Q

What are the two states actin exists in?

A

F-actin and G-actin

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14
Q

What is the polymerized version of Actin called?

A

F-Actin

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15
Q

What is the monomer version of Actin called?

A

G-actin

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16
Q

When phosphorylated, what does cofilin do?

A

Help F-actin build polymers

17
Q

What does cofilin do when unphosphorylated?

A

Severs and depolymerized actin filaments

18
Q

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

A

LTP is induced but rapidly decays

19
Q

What phosphorylates cofilin?

A

LIMK

20
Q

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

A

LTP Is maintained

21
Q

What returns cofilin back to its unphosphorylated stated?

A

Slingshot

22
Q

How are actin filaments connected when not in LTP?

A

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

23
Q

What does the neck of the synapse contain?

A

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

24
Q

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

A

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

25
Q

What happens once cofilin is phosphorylated?

A

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

26
Q

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

A

~30 minutes

27
Q

What do Cell Adhesion Molecules do to stabilize LTP?

A

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

28
Q

What are the two important cell-adhesion molecules?

A

Integrin receptors and N-Cadherins

29
Q

What do integrin receptors do?

A

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

30
Q

What do N-Cadherins do?

A

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

31
Q

What are the 3 main phases of stabilization of LTP?

A

Actin severing, rapid polymerization, cell adhesion

32
Q

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

A

Consolidation

33
Q

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

A

LTP induced but does not last

34
Q

Long lasting LTP depends on both what?

A

Local and activity induced signaling of the genome

35
Q

How does genomic signaling work?

A

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

36
Q

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

A

Synapse to nucleus
Soma to nucleus

37
Q

Describe the synapse to nucleus signaling pathway

A
  • 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
38
Q

Describe Soma to Nucleus signaling

A
  • 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