Synaptic Transmission

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Synaptic Transmission
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Learning objectives A. Using the neuromuscular
junction, identify the important ultrastructural
details. B. Describe the sequence of events from
action potential depolarization of the
presynaptic terminal and neurotransmitter
release. C. Describe synaptic vesicle
recycling. D. List the important
neurotransmitters E. Discuss mechanisms
modulating neurotransmitter release F. Explain
the differences between ionotropic and
metabotropic receptors. G. Explain the sequence
of events occurring upon excitatory
neurotransmitter activation of receptors on the
postsynaptic neuron. H. Be able to diagram the
local currents and explain a graph of current
flow (or potential change) vs. time. I. Explain
the sequence of events occurring upon inhibitory
neurotransmitter activation of receptors on the
postsynaptic neuron. Be able to diagram the
local currents and explain a graph of current
flow (or potential change) vs. time. J. Explain
the concepts of spatial and temporal summation K.
Compare and contrast mechanism of small
neurotransmitter vs. neuropeptide release.
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Neuronal Morphology synaptic spines
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Receptors involved in synaptic transmission
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Metabotropic Receptors and the Autonomic Nervous
System
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The Neuromuscular Junction
Ensheathing Schwann cell
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Axodendritic Synapses
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Axosomatic Synapses
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Release of Synaptic Vesicles requires Ca2.
(pre-synaptic)
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Synaptic Vesicle Cycling.
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Postulated Functions of Synaptic Vesicle Proteins
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Generic synapse
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Neuropeptide Synthesis and Release
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Excitatory and Inhibitory Postsynaptic Potentials
Excitatory postsynaptic potentials (EPSPs)
depolarize the postsynaptic cell bringing it
closer to firing an action potential. EPSPs may
be fast (involving ionotropic receptors) or slow
(involving metabotropic receptors). Excitatory
neurotransmitters include ACh, norepinephrine,
epinephrine, glutamate and serotonin. Inhibitory
postsynaptic potentials (EPSPs) hyperpolarize
the postsynaptic cell to the Cl- equilibrium
potential (-70 mV). Inhibitory neurotransmitters
include g-aminobutyric acid (GABA) and glycine.
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Postsynaptic response to ACh.
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Discuss the relationship between ACh-evoked
conductance and the synaptic response to ACh.
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Reversal of the ACh response.
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IPSP Reversing at Resting Potential
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Graded synaptic potentials initiate action
potentials
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Spatial and temporal summation.
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Voltage clamp
Membrane voltage Command voltage
clamping amplifier
potential amplifier
Current passing electrode
cell
Voltage recording electrode
membrane current
Current-to-voltage converter