Presynaptic Axon Terminal Postsynaptic Membrane Terminal Button Dendritic Spine.
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Transcript of Presynaptic Axon Terminal Postsynaptic Membrane Terminal Button Dendritic Spine.
PresynapticAxon Terminal
PostsynapticMembrane
Terminal Button Dendritic
Spine
(1) Precursor Transport
_ _ _
NT
(2) Synthesis
enzymes/cofactors
(3) Storage
in vesicles
Synapse
Vesicles
NT
Terminal Button
Dendritic Spine
Synapse
Terminal Button
Dendritic Spine
(4) Release
Receptors
Synapse
Terminal Button
Dendritic Spine
AP
Ca2+
Exocytosis
(5) Activation
Quantum releaseEach vesicle contains one quanta of
neurotransmitter (approximately 5000 molecules) – quanta release
(3) Transmitter Inactivation
1. Reuptake by presynaptic terminal2. Uptake by glial cells3. Enzymatic degradation4. Presynaptic receptor5. Diffusion6. Combination of above
(6) Termination
(1) Termination by... Diffusion
(2) Termination by...Enzymatic degradation
(3) Termination by...• Reuptake by presynaptic terminal• Uptake by glial cells
(4) Termination by... Autoreceptors
A
2. Receptor ActivationNS uses 40 families , act on 100 types of receptors; cause EPSPs and IPSPs,
Neuromodulators cause, via 2nd messengers, more complex metabolic effects in the PSM.
Ionotropic channel– directly controls channel– fast
• Metabotropic channel– second messenger systems– receptor indirectly controls channel ~
(1) Ionotropic ChannelsneurotransmitterNTChannel
Ionotropic Channels
NT
Pore
Ionotropic Channels
NT
Ionotropic Channels
NT
G protein: Protein Phosphorylation
Receptor
trans-ducer
primaryeffector
external signal: nt
2d messenger
secondary effector
Receptor
trans-ducer
primaryeffector
external signal: NT
2d messenger
secondary effector
GS
norepinephrine
cAMP
protein kinase
b adrenergic -R
adenylylcyclase
G protein: Protein Phosphorylation
RG
GDP
AC
PK
G protein: Protein Phosphorylation
R
AC
PK
G
GTP
ATP
cAMP
G protein: Protein Phosphorylation
R
AC
PK
G
GTP
ATP
cAMP
P
Pore