Lecture 17: Synaptic Plasticity Part I Flashcards
Name the 3 variables that characterize quantal release.
The number of release sites (N)
Probability of quantal release (p)
The size of quantal response (q)
What are the morphological correlates of N, p and q?
N: number of active zones
p: number of docked vesicles
q: response to a single vesicle
Names the 2 sites of expression and describe them.
Presynaptic: change in amount of transmitter released
Postsynaptic: changes in sensitivity in response to transmitter released.
Summation is only the temporal integration of synaptic inputs due to __________.
Also, what is this known as?
passive properties. Time constant tau
An increase in synaptic strength when action potentials occur in rapid succession is known as?
Synaptic facilitation or paired pulse facilitation (PPF)
What is the synaptic facilitation the result of?
prolonged calcium elevation (residual calcium hypothesis)
What is the target of action on synaptic facilitation?
synaptotagmin
Describe synaptic depression?
Reduction in synaptic strength during successive APs. Results from progressive depletion of vesicle pool
Rate of depression depends on what?
Amount of transmitter released
Calcium channels, AP waveform and neuromodulators can alter __________ at presynaptic terminal.
calcium influx
When an animal becomes less responsiveness to repeated occurrences of a stimulus, this is called what?
Habituation
What is sensitization?
Generalization of an aversive response to a noxious stimulus to other non-noxious stimuli
In a gill motor neuron, sensitization results from activation of the serotonergic modulatory interneuron, which in turn does what?
increases the EPSP at the motor neuron (heterosynaptic)
Describe the short term sensitization activation cascade. involving PKA.
5-HT activates Adenylyl-cyclase, which increases cAMP and then PKA.
What are the 2 effects of PKA?
- Closes K+ channels, leading to broader spikes and more Ca2+ influx = more transmitter release
- increases the release of neurotransmitter
Describe the long term sensitization.
PKA also phosphorylates CREB
CREB stimulates ________ expression, which keep PKA persistently active.
ubiquitin hydrolase
Name the characteristics of early LTP.
- blocked by protein kinase inhibitors
- not blocked by protein synthesis inhibitors
Name the characteristics of late LTP
blocked by translational inhibitors
What are the similarities between changes in synaptic transmission in Aplysia and LTP in mammals?
- Early, transient phase that relies on protein kinases to produce post-translational changes.
- Long lasting phases that need changes in gene expression.
NMDAR dependent LTP is a __________ of synaptic plasticity.
long-lasting form
NMDAR dependent LTP requires activation of ________ by presynaptically released glutamate while postsynaptic membrane is significantly depolarized.
NMDARs
T/F: The rise is postsynaptic Ca2+ concentration activates intracellular signaling cascades that include protein kinases.
True
Maintenence of late LTP requires __________.
Synthesis of new proteins
LTP is accompanied by enlargements of ___________
dendritic spines (and associated postsynaptic densities)
_________ is crucial for NMDAR-LTP:links receptor to CaMKII-alpha
Ca2+ influx
LTP-mechanisms may convert __________ to active mode via AMPAR insertion
silent synapses
Early LTP mostly depends on ___________. Late LTP depends on new ____________.
phosphorylation, gene expression
LTP maintenance remodels the ___________
dendritic spine
Consolidation of ________ requires a symphony of signaling mechanisms and on Translation and Transcription
late-LTP
LTP consolidation requires _______
mTOR
- Natural C-fiber stimulation induces _______ in dorsal horn neuron
LTP
