Lecture 12 Flashcards
__ is needed for the formation of additional synaptic connections
gene expression
late phase effects are thought to be initiated by __ which activates a transcription factor (i.e. __) which stimulates the expression of other proteins ultimately leading to __
protein kinase A; CREB; the generation of new synaptic contacts
what happens to the EPSPs when you add an inhibitory of protein synthesis?
you see short-term potentiation instead, it goes back to normal in a matter of hours
protein synthesis does not affect LTP in __
early stages
T/F: you can’t get new memories (learning, synaptic plasticity) without new neurons
FALSE
LTP is specific to __: just because one synapse is __ doesn’t mean it will have an effect on nearby synapses.
HOWEVER LTP is also __: if one pathway is strongly stimulated and a nearby pathway is weakly (or strongly) stimulated, __
the synapse; strengthened; associative; both synapses will be strengthened
low frequency stimulation on just one synapse with nothing else happening nearby causes __
long-term depression
it is the __ that strengthens the synapse and leads to lasting changes in how signals are transferred between cells
coordinated activity between the presynaptic and postsynaptic elements
results of NMDA receptor knockout mice: (3)
less LTP in hippocampus
less LTD in hippocampus
slow learners in water maze
results of NMDA receptors mutants with increased conductance of channels: (3)
stronger LTP
fast learners in mazes
long-lasting memory
genetic engineering of NMDA receptors affects hippocampal __
synaptic plasticity and learning
at a glutamatergic synapse: during low frequency stimulation, __ is being release from the presynaptic terminal and binding to __ receptors and activating them, giving a little __, also binding to __ receptors but not activating them (because __)
glutamate; AMPA; EPSP; NMDA; we don’t have a great enough EPSP to remove the magnesium)
at a glutamatergic synapse: at high frequency stimulation, there is a lot more __ being released from presynaptic terminal so there are more __ receptors being activated and thus more __ of the postsynaptic membrane (enough to __ allowing __ to flow into the cell)
glutamate; AMPA; depolarization of postsynaptic membrane; enough to remove the magnesium and activate NMDA receptors; calcium
the __ is the trigger for LTP
CALCIUM
we have seen experimentally that LTD perseverates in animals that have been exposed to __ __
ethanol perinatally
different levels of postsynaptic Ca can induce either _ or __
LTP or LTD
protein phosphatases basically act in the opposite way as __
protein kinases
early observations of glutamatergic synapses revealed that stimulation sometimes __
didn’t result in a subsequent response (silent synapses)
silent synapses are prevalent in __ and have also been located in various areas including the __
development; hippocampus
the silence in silent synapses is due to __ and the fact that the postsynaptic cell of these synapses only have __
the magnesium blocking NMDA channels; only NMDA channels, no AMPA
as juveniles, we only have __ receptors at glutamatergic synapses, no __
NMDA; AMPA
hippocampal synapses: LTP enhances these, LTD comes long and diminishes this enhancement - it is this __ that is what’s important - that the synapse can __
dynamic-ness; continuously be enhanced or diminished in response to stimuli
LTD is though to involve a __ in calcium, which activates postsynaptic __ which causes an internalization of the __ receptors and the synapse becomes __
a very low rise in calcium; phosphatases; AMPA; less sensitive
LTD and LTP are predicated on __
changes in the postsynaptic cell and its sensitivity
late stages of LTP are mediated by __
transcription
cell-impermeant molecules: (ex)
neurotransmitters
cell-permeant molecules: (ex)
hormones, steroid hormones, glucocorticoids
cell-associated molecules: only act when other cells are __, hang out on __
in contact with them; the membrane
three classes of cell signaling molecules
cell-impermeant molecules
cell-permeant molecules
cell-associated molecules
G-protein = __-binding protein
GTP
monomeric G-protein: __ interacts with receptor and binds __/__. plays a role in __ (3)
Ras; GTP/GDP; cell differentiation, development, and proliferation
the effect of a signaling molecule is mediated by __
the presence of its receptor
GAP = __. __ GTP and return G-protein to __
GTPase activating proteins; hydrolyze; inactive state
the binding of a signaling molecule causes __ and that triggers a subsequent __ within the cell
a conformational change in the receptor; signaling cascade
4 types of receptors
channel-linked receptors, enzyme-linked receptors, intracellular receptors, and G-protein coupled receptors
what was the first monomeric g-protein discovered?
RAS
monomeric (__) g-protein: relays signals from __ to a __
small; activated cell receptors; intracellular target
heteromeric g-protein coupled receptors: has __ subunits that interact together and with the receptor. __ subunit binds GDP/GTP. __ subunits always work together. __ or __ can be the effector.
alpha, beta, and gamma; alpha; beta and gamma; alpha or beta/gamma
there is lots of __ in the subunits of heteromeric g-proteins
variability (100s of combinations
heteromeric g-proteins have __ targets
diverse
heteromeric g-proteins: alpha subunit either binds to __ and becomes __ or binds to __ which causes it to __
GDP; inactive; GTP; dissociate (leave the other subunits) and go act on the effector protein
heteromeric g-proteins: resting state
when neurotransmitter bind to the receptor, the receptor interacts with __ subunit and exchanges __ for __
__ separates from __, either can act on effector protein
later GTP is hydrolyzed to __ by __
alpha/beta/gamma interact with each other, GDP is bound to alpha
alpha; GDP; GTP; alpha/GTP; beta/gamma; GDP; GAP
4 examples of neuronal second messengers
Ca, cyclic AMP, cyclic GMP, and IP3
cAMP activates __
protein kinase A
