Growth Factors

Question 1

2 Main Functions of Neurotrophins

Answer 1

Increase survival of neurons and regulate formation/maintenance of synapses

Question 2

4 Ntrophins and Their Rs

Answer 2

NGF binds TrkA
BDNF binds TrkB
NT-3 binds TrkC (also A and B)
NT-4/5 binds TrkB

Question 3

Major Point about Rs in PNS

Answer 3

Some peripheral neurons/functions depend on one specific Trk, so if you knock out one might lose altogether

Question 4

p75 R

Answer 4

Initiates cell death if binds Ntrophin or pro-form, or higher affinity for cell survival when complexed w/ Trk

Question 5

Constitutive Pathway

Answer 5

Usually NGF and developmental, pro-protein matures, cleaved by furin, and targeted to constitutive release vesicles. Carried down postsyn retrograde to cell body to stimulate growth cascades

Question 6

Regulated Pathway

Answer 6

Usually BDNF and mature, resistant to furin, pro packaged in secretory granules that accumulate at PM for depol release (can be cleaved by pro-prot convertases there or after release). Also transported to axon terminals of producing cell, and helps there? So autocrine or paracrine

Question 7

3 Mechs BDNF Increases Synaptic Plasticity

Answer 7

Increases # of synapses, conductance of Rs, and expression of Rs

Question 8

BDNF Val66Met Polymorphism

Answer 8

If Met there instead of Val, working memory is worse, in animals has shown lower BDNF levels

Question 9

Chronic Stress Peripheral and 3 Central Effects

Answer 9

Increase peripheral levels of NGF, decrease central levels of NGF, BDNF, and NT-3

Question 10

Aging Effects

Answer 10

Ntrophin Levels same, but Pro levels go up, so maybe p75 causes increased death