Neurotransmitters Flashcards
What is a neurotransmitter ?
4 criteria :
- Synthesis
- Storage
- Release
- Inactivation
Synthesis
The NT must be made in the pre-synaptic neuron
Storage
The NT must be stored presynaptically
Release
The NT must be released on demand
Inactivation
The NT must be inactivated
Inactivation of Neurotransmitters
Reuptake
Enzymal inactviation
Diffusion
Receptor types
Ionotropic
Metabotropic
Main neurotransmitters classified by structure
Amino acids
Biogenic Amines
Peptides
Amino acids
Glutamate
GABA
Glycine
Biogenic Amines
Catecholamines
Noradrenaline
Adrenaline
Dopamine
Serotonin
Peptides
Encephalin
Endorphin
Dynorphin
Primary excitatory NT in CNS
Glutamate
Involved in memory, learning and cell death
Ionotropic receptor
Primary inhibitory NT in CNS
GABA
Acts via ligand gated chloride channels
Glycine
Primary inhibitory NT in spinal cord and brainstem
Synaptic plasticity
Process by which synapses are strengthened or weakened by feedback mechanisms.
Epilepsy
Excess excitation causes a feedback loop
How are GABA proteins inactivated ?
By presynaptic uptake
Tetanus
Clostridium tetani
Inhibits release of glycine
How is tetanus treated ?
Anti-toxins and benzodiazepines
Where are catecholamines synthesised ?
In the bouton and inactivated principally by re-uptake
Parkinsons
Depleted dopamine in motor co-ordination circuits
Schizophrenia
Over production of dopamine
Treatment with antipsychotics
Serotonin
Large family of excitatory and inhibitory receptors in CNS and PNS.
Modulates a range of NTs, e.g. glutamate, GABA, dopamine
Effects of serotonin
Depression
OCD
Some drugs of abuse
Peptides
Made in cell body, transported to the bouton
Endorphins and encephalins
Pain
Emotional perception
Alzheimers disease
Dysfunction of ACh in CNS
Nicotine
Acts on nicotinic acetylcholine receptors in CNS and PNS
Function of anticholineesterases
Prevent the breakdown of ACh; prolongs its activity
Can be therapeutic e.g. Alzheimers
Also toxic ; insecticides; nerve gasses
