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Repair and Regeneration of the Nervous System. What’s Capable of Being Repaired or Regenerated?. Whole Neurons Axons Synaptic clefts Neuromuscular junction Receptors. Whole Neurons. Death is programmed ( apotosis ) or immediated ( necrosis ). If you had too much MSG….
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What’s Capable of Being Repaired or Regenerated? • Whole Neurons • Axons • Synaptic clefts • Neuromuscular junction • Receptors
Whole Neurons Death is programmed (apotosis) or immediated (necrosis)
How Do Axons Know Where To Go? • Blueprint Hypothesis • Axons migrate towards a tissue in a pre-determined manner • Chemical Affinity Hypotheis • Axons migrate towards a tissue based on feedback from “chemoattractants” and “chemorepellants” • Ephrin (retractant), Semaphorins (both)
Synaptic Clefts (Neuromuscular Junction) Principles of Neural Science (Kandel); Chapter 55
Formation of a Neuromuscular Junction • Growth cone approaches a new formed myotube • Forms an unspecialized contact • Multiple axons converge on a single site • All but one are eliminated • Survival of the fittest Principles of Neural Science (Kandel); Chapter 55
What Happens With a Loss of Nerve and Tissue? Principles of Neural Science (Kandel); Chapter 55
Differentiation of Synaptic vs. Non-synaptic Regions Principles of Neural Science (Kandel); Chapter 55
Receptor Aggregation Neuregulin: enables the formation of AcH receptors at the neuromuscular junction
Cytoplasmic Proteins • link receptors together
Macromolecular Complexes • link pre- and post-synaptic membranes together Principles of Neural Science (Kandel); Chapter 55
Neurotrophic Factors • Guide neuron survival and outgrowth on neurons • BDNF, NT-3, NT-4 and 5 • Hot factor to study beyond neuron repair and regeneration (drug addiction)
Spinal Cord Regeneration with Channel Rhodopsin • Achieved through optogenetics http://www.scientificamerican.com/video.cfm?id=method-of-the-year-2010-12-22