Neurotransmission Flashcards
What is neurotransmission?
A chemical messenger that sends signals from a neurone to a target cell across a synapse
What are the two classes of neurotransmitters?
Inotropic and metabotropic
What are inotropic neurotransmitters?
Ligand-gated ion channels
What are metabotropic neurotransmitters?
G-protein coupled receptors
What are the three criteria for a neurotransmitter?
- Molecule must be synthasised and stored in the presynaptic neurone to be released
- Molecule must be released upon stimulation
- Once released, molecule must produce a response in the postsynaptic cell
What type of receptor has direct opening?
Ligand-gated ion channels
What type of receptor has indirect opening?
G-proteins coupled receptors
How do ligand gated ion channels work?
When neurotransmitter binds to receptor, ion channel opens and sodium ions flow into the cell causing an action potential
How do G-protein coupled receptors work?
Neurotransmitter binds to receptor (coupled with g-proteins). g-proteins activate the effector protein which opens the ion channels
What does GABA mean?
Gamma aminobutyric acid
What is GABA?
The major inhibitory neurotransmitter in the CNS
What does GABA lead to?
Hyperpolarisation - an increase in negative charge, and inhibits firing of an action potential
What are the two types of GABA?
GABAa - ligand gated
GABAb - g-protein
What is glutamate?
Major excitatory neurotransmitter in the CNS
What does glutamate do?
Activates ligand gated ion channels and g-protein
What role does glutamate have?
Learning and memory via long term potentiation
What is acetylcholine important for?
Neuromuscular junction, learning and memory
What does acetylcholine activate?
Nicotinic and muscarinic Ach receptors
What is dopamine?
Has a role in movement, motivation, and reward
What pathway does dopamine use to regulate movement?
Nigrostriatal pathway
What does dopamine activate?
G-protein coupled with receptor sub-types (D1-D5)
What is serotonin?
Has a role in sleep, mood and emotional behaviours
What does serotonin activate?
G-protein and ligand-gated ion channels
What is noradrenaline?
Has a role in fight or flight, attention, arousal, and sleep
