NEUROCHEMISTRY
1. Definition
This is the specific study of neurochemicals including neurotransmitters and other molecules
(such as psycho-pharmaceuticals) that influence the function of neurons and how these
neurochemicals influence the network of neural operation.
2. Neurotransmitter
Neurotransmitters are chemicals that are used to relay, amplify and modulate electrical signals
between neuron and another cell.
3. Criteria for classifying a molecule a neurotransmitter
There are three criteria for a chemical to be classified as a neurotransmitter. It must be;
1) Synthesized and stored in pre-synaptic terminals
2) Released from terminals upon stimulation
3) It must have specific receptors on the postsynaptic cells
Synthesis and storage of the chemical can be demonstrated with immunocytochemistry and in
situ hybridization. Release of the chemical upon stimulation can be shown with a chemical
assay. The presence of the receptors can be demonstrated with neuro-pharmacological methods
or autoradiography
4. Classes of Neurotransmitters
Amino Acids Amines Peptides Others
GABA Acetylcholine (ACh) Cholecystokinin (CCK) Opiates
Glutamate (Glu) Dopamine (DA) Dynorphin Gases (NO, CO)
Glycine (Gly) Epinephrine Enkephalins (Enk) Lipids
Aspartic Acid Histamine N-acetylaspartylglutamate (NAAG) Endocannabinoids
1
, Norepinephrine (NE) Neuropeptide Y
Serotonin (5-HT) Somatostatin
Substance P
Neurotensin
Vasopressin
5. Functions of Neurotransmitters
Groups Neurotransmitter Function
Acetylcholine Acetylcholine Excitatory
Epinephrine Excitatory
Amines Norepinephrine Excitatory
Dopamine Excitatory and Inhibitory
Serotonin Excitatory
Amino Acids Glycine Mainly Inhibitory
γ-Aminobutyric Acid (GABA) Inhibitory
6. Characteristics of Neurotransmitters
a) Synthesis, Transportation and Packaging
Neurotransmitters are synthesized, transported and packaged in slightly different ways
depending upon whether they are small molecule neurotransmitters or neuropeptides.
Small molecule neurotransmitters are synthesized by cytosolic proteins which are slowly
transported to the terminal. In the terminal, synthesis of the neurotransmitter occurs.
2
1. Definition
This is the specific study of neurochemicals including neurotransmitters and other molecules
(such as psycho-pharmaceuticals) that influence the function of neurons and how these
neurochemicals influence the network of neural operation.
2. Neurotransmitter
Neurotransmitters are chemicals that are used to relay, amplify and modulate electrical signals
between neuron and another cell.
3. Criteria for classifying a molecule a neurotransmitter
There are three criteria for a chemical to be classified as a neurotransmitter. It must be;
1) Synthesized and stored in pre-synaptic terminals
2) Released from terminals upon stimulation
3) It must have specific receptors on the postsynaptic cells
Synthesis and storage of the chemical can be demonstrated with immunocytochemistry and in
situ hybridization. Release of the chemical upon stimulation can be shown with a chemical
assay. The presence of the receptors can be demonstrated with neuro-pharmacological methods
or autoradiography
4. Classes of Neurotransmitters
Amino Acids Amines Peptides Others
GABA Acetylcholine (ACh) Cholecystokinin (CCK) Opiates
Glutamate (Glu) Dopamine (DA) Dynorphin Gases (NO, CO)
Glycine (Gly) Epinephrine Enkephalins (Enk) Lipids
Aspartic Acid Histamine N-acetylaspartylglutamate (NAAG) Endocannabinoids
1
, Norepinephrine (NE) Neuropeptide Y
Serotonin (5-HT) Somatostatin
Substance P
Neurotensin
Vasopressin
5. Functions of Neurotransmitters
Groups Neurotransmitter Function
Acetylcholine Acetylcholine Excitatory
Epinephrine Excitatory
Amines Norepinephrine Excitatory
Dopamine Excitatory and Inhibitory
Serotonin Excitatory
Amino Acids Glycine Mainly Inhibitory
γ-Aminobutyric Acid (GABA) Inhibitory
6. Characteristics of Neurotransmitters
a) Synthesis, Transportation and Packaging
Neurotransmitters are synthesized, transported and packaged in slightly different ways
depending upon whether they are small molecule neurotransmitters or neuropeptides.
Small molecule neurotransmitters are synthesized by cytosolic proteins which are slowly
transported to the terminal. In the terminal, synthesis of the neurotransmitter occurs.
2
