Regeneration in CNS and PNS

Question 1

Name 4 treatments for spinal cord injury?

Answer 1

-spinal decompression
-Neuroprotection
-rehabilitation
-Assistive devices

Question 2

Example of an animal that can fully regenerate their spinal cord?

Answer 2

lampreey can fully regenerate their entire spinal cord.

Question 3

Describe axon regeneration in the CNS?

Answer 3

it fails due to the inhibitory enviroment and lack of intrinsic regeneration ability.

Question 4

Describe axon regeneration in PNS?

Answer 4

PNS axons regenerate because they have intrinsic regenerative markers.

Question 5

How long do schwann cells remain permissive to peripheral nerves?

Answer 5

2-3months

Question 6

What is the problem with how long schwann cells persist?

Answer 6

peripheral neurons only grw by 1mm a day so if its a longer nerve then the schwann cells may not last long enough

Question 7

How long do muscle plates have before they lose their ability to become re-inervated?

Answer 7

1 year

Question 8

What is the criteria for regeneration and repair success of neurons?

Answer 8

-neuronal cell survival
-axon elongation
-axon guidnace target
-appropriate targeting

Question 9

what is the critical period of the nervous system?

Answer 9

The time during which reduction of neuronal numebrs, remodelling of synapses and strengthening of connections. most vulnerable to external stimuli.

Question 10

what is a perineuronal nets (PNNs)?

Answer 10

specialized extracellular matrix structures responsible for synaptic stabilization in the adult brain.

Question 11

How does membrane collapse occur ingrowth cone formation?

Answer 11

destruction of the membrane causes calcium influx and membrane depolarises releasing more calcium.
Ca2+ activates calpains which digest Actin and MTs become depolymerised, leads to membrane collapse.

Question 12

How does the membrane reseal itself during growth cone formation?

Answer 12

Ca2+ levels decrease again due to a sealing patch so actin and MTs repolymerise. the repolymerisation leads to force being generated at the leading edge at the lamellipodium.

Question 13

What happens if calcium isnt present during growth cone formation?

Answer 13

regeneration fails and a static endbulb is formed.

Question 14

what three molecules are expressed that inhibit axon regeneration?

Answer 14

Nogo-A, MAG and OMgp

Question 15

what does MAG do?

Answer 15

localised to mature myelin, stabilsies the neuronal network

Question 16

what does Nogo-A do?

Answer 16

Acts through a receptor complex involving p75 and NgR affecting axonal growth via calcium and RhoA signalling.

Question 17

what does OMgp do?

Answer 17

GPI anchored protein expressed by neurons that mediates cell-cell interaction at nodes of reniver.