Neurotransmitter and Receptor Diversity Flashcards
What happens when an action potential reaches the synaptic terminal?
Neurotransmitters are released and diffuse across the synaptic cleft, the receptors see the NT and initiate a response
How do receptors respond to NT?
Direct excitatory or inhibitory neurotransmission - the next cell fires an AP or is inhibited
Neuromodulation - alters the pre synaptic cells ability to release more NT or the post synaptic ability to respond
What are the two categories of neurotransmitters?
Classical
Non classical
What are classical neurotransmitters?
Amino acids - GABA, glutamate
Monoamines - dopamine, serotonin
Acetylcholine
What are non classical neurotransmitters?
Neuropeptides e.g. endorphin
What is the difference between classical and non classical neurotransmitters?
Classical - synthesised at the pre synaptic terminal, stored in vesicles, released when calcium comes in
Non classical - synthesised in the cell body and transported to the synaptic terminal, stored in secretory granules, released in response to global increase in calcium, need way more calcium for them to be released
What are amino acid transmitters responsible for?
Fast transmission, turning on or off neurons
What are examples of amino acid transmitters?
Glutamate - excitatory, causes the next neuron to fire a nerve impulse
GABA and glycine - inhibitory, blocks the next neuron from firing an impulse
What do receptors vary in?
Their pharmacology - what transmitter binds to the receptor and how drugs interact
Kinetics - rate of transmitter binding and channel gating determine the duration of effects
Selectivity - what ions are fluxed, allowing certain things in but not others
Conductance - how fast something flows inside the receptor
Types of receptors
Agonist - a drug that combines with a receptor on a cell to produce an action
Antagonist - a drug that reduces or completely blocks the activity of the agonist, no effect after interacting with receptor. Alone, doesn’t do much but with agonist, blocks the activity of it
4 requirements for a neurotransmitter
Chemical synthesised presynptically
electrical stimulation leads to the release of the chemical
chemical produces physiological effect
terminate activity
What is the difference between glutamate and GABA?
Glutamate binds to iontotropic receptors, influx of Na, causing a EPSP - depolarising - EXCITATORY
GABA inotropic receptors, influx of calcium, causing an IPSP - hyper polarising - INHIBTORY
What else activates ionotopic receptors?
Acetylcholine and serotonin and ATP
What does input have to be?
Integrated, all the charges will then decide whether a postsynaptic neuron will fire an AP or not
How can you release non classical neurotransmitters?
A more intense stimulation is needed - hence a more global increase in calcium