Presynaptic Axon Terminal Button Postsynaptic Membrane Dendritic Spine
Presynaptic Axon Terminal Button Postsynaptic Membrane Dendritic Spine
(1) Precursor Transport
(2) Synthesis _ _ _ enzymes/cofactors NT
(3) Storage in vesicles
NT Terminal Button Dendritic Spine Synapse Vesicles
(4) Release Terminal Button Dendritic Spine Synapse Receptors
Terminal Button AP Dendritic Spine Synapse
Exocytosis 2+ Ca
(5) Activation
Quantum release Each vesicle contains one quanta of neurotransmitter (approximately 5000 molecules) – quanta release
(3) Transmitter Inactivation 1. 2. 3. 4. 5. 6. Reuptake by presynaptic terminal Uptake by glial cells Enzymatic degradation Presynaptic receptor Diffusion 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 Activation NS uses 40 families , act on 100 types of receptors; cause EPSPs and IPSPs, Neuromodulators cause, via 2 nd messengers, more complex metabolic effects in the PSM. Ionotropic channel – directly controls channel – fast • Metabotropic channel – second messenger systems
(1) Ionotropic Channels Channel NT neurotransmitter
Ionotropic Channels NT Pore
Ionotropic Channels NT
Ionotropic Channels NT
G protein: Protein Phosphorylation external signal: NT nt norepinephrine Receptor b adrenergic -R transducer primary effector GS adenylyl cyclase 2 d messenger c. AMP secondary effector protein kinase
G protein: Protein Phosphorylation A C R G GDP PK
G protein: Protein Phosphorylation A C R G ATP GTP c. AMP PK
G protein: Protein Phosphorylation A C R G ATP GTP P c. AMP PK Pore
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