Synaptic Transmission: A Four Step Process

I. Synthesis and Storage of Neurotransmitters

A. Synthesis of small molecule neurotransmitters

1. Acetylcholine: a representative small molecule neurotransmitter
2. Uptake of choline, a precursor of acetylcholine
3. Choline acetyltransferase: the binding of choline and acetate
4. Storage of acetylcholine in vesicles
5. Clinical Application: Acetylcholine and Alzheimer's Disease

B. Synthesis of neuropeptide neurotransmitters

1. Endorphins: a representative family of neuropeptide neurotransmitters
2. Translation of genomic message to endorphin prepropeptide
3. Packaging, transport and final processing of the endorphin propeptides
4. Arrival of the synthesized peptide at the terminal
5. Clinical Application: Endorphins and Autism

II. Neurotransmitter Release

A. Vesicles: two types, one process

1. Calcium influx: initation of neurotransmitter release
2. Mobilization of synaptic vesicles
3. Role of specialized proteins
4. Vesicle docking, fusion, and exocytosis
5. Recycling of synaptic vesicles

III. Neurotransmitter Postsynaptic Receptors

A. Ionotropic (ligand-gated) receptors

1. GABAa receptors: a representative family of ligand-gated receptors
2. GABAa receptor function: inhibitory postsynaptic potentials
3. Postsynaptic GABA recognition by its receptor
4. Binding of GABA to receptor
5. Structure of the GABAa receptor
6. Ion channel opening: mechanism of action
7. Positive neuromodulation of GABAa receptors: tranquilizers
8. Negative neuromodualtion of GABAa receptors: anxiogenics
9. Clinical Application: GABA and Anxiety

B. Metabotropic (G-protein coupled) receptors

1. Dopamine Receptors: a representative family of metabotropic receptors
2. Dopamine D1 receptor
3. Function of the G-protein
4. G-proteins, cAMP, and ion channel opening
5. Dopamine receptor blockade: antipsychotic drugs
6. Clinical Application: Dopamine and Schizophrenia

IV. Inactivation of Neurotransmitters

A. Enzymatic inactivation of neurotransmitters

1. Acetylcholinesterase: a representative inactivation enzyme
2. Location, structure and function of acetylcholinesterase
3. Enzyme inhibition: anticholinesterases
4. Clinical Application: Acetylcholine, Nerve Gas and Myasthenia Gravis

B. Presynaptic transporters: inactivation of neurotransmitters by reuptake

1. Serotonin transporter: a representative reuptake pump
2. Location and structure of the serotonin transporter
3. Mechanism of action of the serotonin transporter
4. Transporter inhibition: selective serotonin reuptake inhibitors
5. Clinical Application: Serotonin and Depression

© Williams College Neuroscience, 1998