Lecture 18: Synaptic Plasticity Part II Flashcards
__________ is the opposing process to LTP
Long term depression (LTD)
T/F: LTD may serve to counteract otherwise steadily decreasing levels of potentiation.
False, steadily increasing
LTP can be actively reversed by _________ stimulation of NMDA-Rs, which leads to LTD.
low-frequency
LTP results from brief, high frequency stimulation, but LTD occurs when a pathway id stimulated at a _______ for a __________.
low rate, long time
LTD is blocked by what two antagonists?
NMDAR and calcineurin
What are 3 main characteristics that LTP and LTD share?
- lasts for several hours
- input specific
- can erase the increase in EPSP size
LTD is initiated by what?
small and slow increases in Ca2+ trigger depression
LTP is initiated by what?
large and fast trigger potentiation
LTD results mainly from a decrease in _____________.
postsynaptic AMPA receptor density
LTD results from activation of what?
Ca2+ dependent phophatases which internalizes AMPARs
Different increases in Ca2+ concentration determine threshold and extent and direction of ___________.
synaptic strengthening
Hippocampal LTD depends on?
NMDA receptors
mGluRs
endocannabinoids
AMPA receptor trafficking and kinase vs. phosphatase activity defines ________.
LTP vs. LTD
Fragile X is caused by a mutation in the _______ gene
FMR1
FMRP binds and transports __________.
mRNAs
Loss of FMRP leads to what?
excessive dendritic arborization
Impaired synaptic plasticity can result in what?
- Increased mGluR LTD
- Decreased LTP
- Immature dendritic spine architecture
Deficits in LTP in Fragile X are related to what?
mGluR dependent translational mechanisms. mGluR mediated events will be enhanced or absent Blocking mGluR 1 and 5 will rescue these deficits.
What drug could prove useful in finding a target in Fragile X?
Fenobam
PKMζ is an atypical ______.
PKC. Lacks a regulatory subunit and is autonomously activated once it’s translated.
PKMζ is sufficient to _____ LTP
induce
PKMζ moves _________ to the synapse.
AMPARs
PKMζ is inhibited by ZIP. What does ZIP do?
Reverses late-LTP and causes established memory decay.
