Darkthorn’s Blog

PNS

• • nerve fibres regenerate depending on their location

• • Schwann cells guide the regeneration of cut axons

CNS

• • repair and functional regeneration is limited

  • myelin associated inhibitory factors

  • astrocyte scar formation and age related decline in repair mechanisms

Spinal Cord Damage

• • mainly due to cell death, inflammation, expanding cysts and glial scarring, also degenerating tracts, demylination and atrophied muscles

  • some spontaneous repair – gliogenesis, sprouting axons, cortical sensory motor arrangement, some rubriospinal compensation

  • prevents expansion of critical damage, create bridges, promote axon regeneration, compensate for demylination, replace dead cells

  • parapligia or quadriplegia

Parkinson’s Disease

• • disordered control over movements

  • loss of dopaminergic neurons in pars compacta of substancia nigra

  • actions - increase L-dopa, inhibit degradation by MAO-B, stimulate release of dopamine, block action of Ach in striatum

  • mechanisms – overactive glutamate producing cells affected by free radicals

Stem Cells

• • stem/progenitor cells are self renewing and can be used for gene therapy

  • can differentiate into neurons or glia

  • neurosphere – a clone of cells from a single neural stem cells (multipotent)

  • can be treated with factors for promoting neural differentiation

Other Pathways

• • growth and migration factors

  • functional integration (axon growth and guidance molecules)

  • increase in the number of neurons