Neuro17 - 22 Flashcards
Why is regeneration in the nervous sytem important?
Damage very serious
What are the two forms of PNS damage?
Crush or severance
Does PNS damage lead to cell death?
Depends on proximity to cell body
What is the result of denervating muscle?
Atrophy, AChR reversal to embryonic, MUSK increase
What helps denervated muscle?
External electrical stimulation - prevents atrophy
What does nervous regeneration require?
Schwann cells, supply of GFs, degree of sprouting from growth cone
Which kind of nervous injury has better prognosis?
Crush
Outline recovery of spinal cord injuries
Poor connection recovery - sprouting usually followed by failed regeneration, and degeneration (aspects of Wallerian degeneration). Cysts and glial scars tend to form
What do CNS neurons avoid?
Oligos
What improves CNS regeneration?
Removal of myelin and oligos, autoimmunisation to myelin
Name a myelin protein that inhibits axon growth
Nogo-a
Characterise Nogo-a
200kD - in oligos and developing neurons
Characterise Nogo-b
55kD - in many cells
Characterise Nogo-c
25kD - in muscle
Outline some objections to the involvement of Nogo in nervous regeneration
No correlation between nogo and regenerative capacity, transplanted hippocampal neurons grow axons into myelin, musch myelin is removed by macrophages after damage, grey matter regen is poor too
What are CSPGs?
Condroitin sulphate proteoglycans
How are astrocytes supposedly involved in nervous regeneration?
Form glial scar - jumbled and fibrous - perhaps these impair regen
How can we repair nervous damage?
Spinal cord bridges, foetal cell transplant, umbilican cell transplant, autologous transplants
What are spinal cord bridges?
Plastic tubing filled with GFs, ECM synthetic matrix etc
Where are adult nervous stem cells?
Hippocampus, olfactory epithelium, forebrain SVZ, dentate gyrus
Explain the connection between anti-depressants and stem cells
Maybe promote new cell growth, hence why they take a few weeks to work
