Flashcards in Lecture 21 Deck (12):
What is NGF? Where does it work in the nervous system?
Nerve growth factor
Describe the mechanism by which a neurotrophin binds to a neuron.
Receptor-neurotrophin complex endocytosed
Retrograde transport to nucleus
Neurotrophin regulates gene transcription and biologic processes to keep the neuron alive
What is BDNF and NT3? Where do they work in the nervous system?
BDNF = brain derived neurotrophic factor
NT-3 = neurotrophin 3
Variety of PNS and CNS neurons
What are the neurotrophic receptors? What is their mechanism?
trk = tyrosine related kinases
Neurotrophin binds as a dimer - receptor dimerizes
Each receptor activates kinase to phosphorylate the tyrosine residues on its partner
Downstream pathways that promote neuron survival
What is BDNFs autocrine mechanism?
If have Ca2+ present --> cell can be depolarized via excitatory synapses
Then neurons make more BDNF --> promotes more survival
Explain how the neurotrophic hypothesis can be bidirection.
Target releases neurotrophin to keep neuron alive
Neuron excites target via depolarization --> induces BDNF release
How does BDNF affect a cell type in the developing cortex?
Determines which lamina a neuroblast will enter
How does BDNF change dendrites?
Need just the right amount to get right dendrite shapes and spine growth
Allows for neuronal plasticity in the adult brain
Explain the relationship between BDNR (and its receptor) and learning vs memory recall.
BDNF is necessary for learning
Not needed for expression of conditioned learning aka memory
How is BDNF secreted?
Cleaved by extracell enzymes into active form
What genotype is associated with cognitive dysfunction?
Decreased cortical and hippocampal volume