NNN Flashcards
an entry of + ions results in what charge change
positive (depolarisation or excitation)
an exit of + or entry of - ions results in what charge
negative (hyperpolarisation or inhibition)
a drug that is an agonist of a Na channel does what
opens the channel, causing cell excitation
a Na antagonist does what to the channel
closes channel, stops ion flow and favours inhibition
a drug that is an agonist of a K channel does what
opens the K channel and causes K flow out of the cells, makes cell more negative (inhibitory)
a K channel antagonist does what to the channel
closes the K channel, retains the K in the cell and favours positive rmp and is therefore excitatory
depolarisation at the synapse causes what ions to enter the cell
Ca
calcium entry triggers what
exocytosis of synaptic vesicle contents
neurotransmitter binding initiates a response where
in the post synaptc cell
neurotransmitters can be returned to axon terminals for what
reuse or transported into glial cells
enzymes (inactivate/activate) neurotransmitters
inactivate
neurotransmitters can diffuse out of what
the synaptic cleft
what are glutamate transporters required for
high rates of information transmission at excitatory synapses in the CNS
how many modes of action are there in the “post synaptic action”
2
what are the 2 modes of action
ionotropic and metabotropic
direct gating is by what mode of action
ionotropic receptors
indirect gating is by what mode of action
metabotropic receptors
gabe has what structure
pentamer
glycine has what structure
pentamer
nicotinic ach has what structure
pentamer
glutamate receptor has what structure
tertameric
glutamate is the major ______ neurotransmitter but may also have inhibitory effects via what kind of receptors
excitatory
metabotropic glutamate receptors
ionotropic glutamate receptors ____ gate ion channels
directly
NMDA receptor controls a channel permeable to what ions
Na, Ca2+, and K+
Kainate and AMPA channels are permeable to what ions
Na, and K+
ampa and kainate mediate ____ excitatory synaptic transmission in the CNS
fast
nmda contributes to a ____ component to the excitatory synaptic potential
slow
ketamine influences the nmda receptor how
blocks
metabotropic glutamate receptors dont have what
intergral ion channel
how do metabotropic glutamate receptors exert their effects
second messenger cascade
GABA is the main what in the CNS
inhibitory neurotransmitter
GABA acts on how many receptors
2
ionotropic GABAa receptors operates what ion chanel
Cl-
GABAb is what kind of receptor
metabotropic
GABAb metabotropic receptor ofetn activates what ion channel
K+
what do benzodiazepines do to GABA
positive allosteric modulators - enhance Cl entry
how does baclofen influence the funtion of GABAb receptors
agonist, enhances the K current (increases inhibition)
glycine is what kind of neurotransmitter
inhibitory
where does glycine exret its effects
glycine ionotropic receptor
what ions are involved in glycine ionotropic receptors what what other neurons does it impact
Cl-
inhibits antagonstic muscles motorneurons
hoq quick is ionotropic gating of ion channels
rapid
why cant (most of the time) metabotropic receptors trigger an action potential
too slow
Normally the slow actions of metabotropic receptors are insufficient to trigger an action potential so they have
modulatory synaptic actions
what do modulatory synaptic actions allow the metabotropic receptors to do
acting on channels in the presynaptic terminal to modulate transmitter release
metabotropic can influence ion channels how?
by being able to open and close them
fast EPSP is due to activation of what
nicotinic ach receptors
what ions do nicotinic ach receptors conduct
NA and K
slow epsp follows activation of what
muscarinic (GPCR) ach receptors
IPSP’s are caused by the release of what
inhibitory neurotransmitters
the strength of a graded potential diminishes over distance due to what
current leak and cytoplasmic resistance
the amplitude increases in a graded potential as what ion enters
Na
the higher the amplitude of a graded potential the …
the further the spread of the signal
if a graded potential does not go beyond the threshold at the trigger zone ….
an action potential will not be generated
the duration of an action potential depends on what
kinetics of activation of the contributing ionic conductances
action potential of most neurons aee followed by what
a marked afterhyperpolarisation
the amplitude of the AHP is usually close to the calculated what
Ek
glutamate neurotransmission results in what
excitation
GABA neurotransmission results in what
inhibition
neurotrasmitters are released in discrete packages called what
quanta
the number of quanta released varies with what
the stimulus
what is a stretegy used to increase quantal release
extensive innervation
what is an example of a mega humongous presynapse
calyx of held synapse
where is the calyx of held synapse
superior olivary complex
purkinje cells are inervated by what kind of fibres
climbing fibres
each parallel fibre contacts multiple what
purkinje cells
what is spatial summation
EPSP and IPSP are spatially distributed but times together
what is temporal summation
EPSP occur in temporal sequence such that threshold is triggered
both LTS and FS cells are interneurons releasing what
GABA
intercotrical excitatory neurons can evoke responses where
in LTS cells
FS cells innervate (release GABA where)
other FS cells
RS cells
LTS cells
LTS cells innervate (release GABA where)
FS cells
RS cells
but not on LTS cells
RS cells innervate (release glutamate where)
LTS cells
RS cells
FS cells
FS and LTS are _______ RS cells are not
electrically coupled
a netwrok of electrical coupled interneurons drives synchronised what
inhibition in neocortex
ACPD stimulation activates what cells and what does thic cause
LTS cells
synchronous IPSP’s in F cells
GRanule cells and inferior olivary cells are in conrtol of what neurotransmitter
glutamate
Purkinje celld are in control of what neurotransmitter
GABA
each purkinje cell is directly innervated by what
a single climbing fibre
granule cells axons ascend where
molecular layer
granule cells ascend to the molecular layer where they
bifurcate into parallel fibres
climbing fibers regulate relatively low what
low discharge of purkinje cells complex spikes
sensory systems code for what
modality, intensity, location, and duration of external stimuli
where does the process of coding start
receptors
each unique type os sensation is called what
sensory modality
receptove fields is defined by what
a region of sensory space whose stimulation results in a change in discharge of the neuron
the most basic mechanism for identifying the nature of sensory input is via what
labeled lines
a common principle is used for estimating where a stimulus is loacated - what is this celled
topographic mapping
