Synapse Formation and Elimination

Question 1

Post-synaptic differentiation

Answer 1

AchR clustering

Question 2

Prepatterning

Answer 2

Primitive, prior to arrivial of axon
- clusters are broad an undefined in muscle fibres

Question 3

Clustering

Answer 3

innervation of axon - large clusters develop in synaptic region

Question 4

What is the determining factor for AchR clustering

Answer 4

Release of agrin from nerve terminal

Question 5

Agrin

Answer 5

signal for post-synaptic differentiation
- gets trapped in BL
- binds to LRP4 receptors on post-synaptic membrane

Question 6

at what day does one axon usually take over the occupancy of another?

Answer 6

Postnatal day 15

Question 7

What is the initiator of interaxonal competition

Answer 7

Switch from synchronous to asynchronous

Question 8

alpha-bungarotoxin

Answer 8

irreversible competitive antagonist of AchR
- block NTs to these sites

Question 9

Significance of post-synaptic activity

Answer 9

Crucial for the maintenance of synapses
- converts pro to mature BDNF - protects against retraction

Question 10

When does synchronised firing occur

Answer 10

early in development and switched with asynchronous soon after birth

Question 11

Pro-BDNF (receptor and effect)

Answer 11

p75NTR
negative effect - apoptosis

Question 12

mBDNF (receptor and effect)

Answer 12

TrkB
positive effect - neuronal survival

Question 13

Responsible for intracellular cleavage

Answer 13

furin
proconvertase

Question 14

Responsible for extracellular cleavage

Answer 14

MMP7/9

Question 15

Fluorogenic proteolytic beacon assay

Answer 15

Used to show that proteolytic cleavage of BDNF (P-M) is essential for synaptic competition and elimination

Question 16

mBDNF and TrkB signalling

Answer 16

prevents synaptic retraction at the active terminals

Question 17

proBDNF in unstimulated neuron

Answer 17

stimulates retraction

Question 18

consequence of mBDNF

Answer 18

maintanence

Question 19

consequence of proBDNF

Answer 19

retraction