Neuroscience 6 - Neurotransmission Flashcards
What are the key wualities of synaptic transmission?
- Rapid
- Diverse
- Adaptable
- Plasticity (ability to change the strength and structure)
- Learning and memory
What are the three stages of synaptic transmission?
1) Biosynthesis, packaging and relase of neurotransmitter
2) Receptor action
3) Inactivation
List the types of molecules neurotransmitters can be and give examples.
- Amino acids (glutamate most abundant, GABA and glycine)
- Amines (noradrenaline, dopamine)
- Neuropeptides (opiod peptides, least common)
Describe the process that occurs causing neurotransmitter release
- Vesicles are filled
- Proteins on the surface of the vesicle bind to proteins on the presynaptic membrane, making the vesicle primed
- Calcium ions flood in due to action potential. Activates a calcium sensor in the protein complex, which stimulates opening of a pore and release of neurotransmitters.
Which toxins target vesicular proteins?
- Tetanus toxin (C.tetani) causes paralysis, affecting vesicular proteins
- Botulinum toxin affects vesicular and docking proteins
- Alpha latrotoxin stimulated transmitter release depletion
What are the two types of receptor in the postsynaptic membrane?
- Ion channels, which mediate fast transmission
- G protein coupled receptors, which are slower and effectors are enzymes or channels
What ion channel receptors are used in the CNS and PNS.
CNS:
- Glutamate
- Gama amino butyric acid (GABA)
PNS:
- Acetylcholine at nicotinic receptors
What G protein coupled receptors are used in the CNS and PNS?
- Dopamine
- Noradrenaline
- Neuropeptides
Which receptors are inhibitory, and which are excitatory?
- Glutamate is excitatory
- GABA is inhibitory
What are the two types of glutamate receptors?
- AMPA receptors
- NMDA receptors
What are the characteristics of AMPA receptors?
- Fast excitatory synapses
- Rapid onset and offset
What are the characteristics of NMDA receptors?
- Opens once an action potential has been stimulated.
- Allows sodium and calcium entry
- Calcium modifies the AMPA recepto and affects protin synthesis, affecting synapse formation
- Important in learning and plasticity
How does reuptake of glutamate from the synapse occur?
- Excitatory amino acid transporter EAAT carries glutamate to the glial cell and presupynaptic neurone
- Glutamate is converted to glutamine by glutamine synthetase
Describe the reuptake of GABA.
- GABA transporter (GAT) carries the GABA into the glial cell and presynaptic neurone
- Here it is converted into succinate dehydrogenase by GABA transaminase (GABA T)
What is GABA made from?
Glutamate
