Neurotransmitters Flashcards
What components of a neurone are concerned with information reception, integration and rapid transfer?
Describe the range in abundance of neurones and rate of their transmission
Vary in abundance from nM to mM CNS tissue concentrations
May mediate rapid (µs - ms) or slower effects (secs)
What are the 3 large groups of NTs?
Amino acids
Amines
Neuropeptides
Where are synaptic vesicles docked in a neurone?
In the synaptic zone
What are the targets for neurotoxins?
Vesicular proteins
What are the mechanisms of botulinum toxin and alpha latrotoxin?
B-toxin:Inhibits release of NTs from axon
A-latrotoxin:Increases uptake of Ca2+
When an NT vesicle release dependent on?
Ca2+
What type of receptor mediates all of the slow enzymatic transmission?
G-coupled receptors
What type of receptor mediates all of the fast excitatory and inhibitory transmission?
Ion channels
Give some examples of the use of ion channels in the nervous system?
Give some examples of the use of G-coupled receptors in the nervous system?
What molecules do
Glutamate,
Glycine,
GABA
ion channels allow passage for, and what does the influx of these molecules lead to?
Glutamate:Na+>Depolarisation
GABA:Cl->Hyperpolarisation
Glycine:Cl->Hyperpolarisation
What feature of ion channels gives them distinct functional properties between them?
Multiple subunit makeup
What does this graph represent?
An excitatory post-synaptic potential
What does this graph represent?
An inhibitory post-synaptic potential
What are the 2 types of glutamate receptors, what else is required for activation of both and which is fast and slow and why?
Glycine also needed as a co-agonist
Why: Ca2+ acts as 2nd messenger
What occurs in an excitatory glutamate synapse?
Glutamate synthesised from glucose via TCA cycle & transamination
Glutamate reversibly binds postsynaptic receptors (linked to ion channels)
Rapid uptake of glutamate by excitatory amino acid transporters (EAATs)
Glutamate enzymatically modified by glutamine synthetase to glutamine in glial cells
What occurs in an inhibitory GABA synapse?
GABA synthesised by decarboxylation of glutamate by glutamic acid decarboxylase (GAD)
GABA reversibly binds post-synaptic receptors (linked to ion channels)
Rapid uptake of GABA by GABA transporters (GATs)
GABA enzymatically modified by GABA-transaminase (GABA-T) to succinic semialdehyde (glial cells & GABA nerve terminals)
What molecule leads to abnormal cells firing causing seizures?
Excess GLUTAMATE in the synapse
Aetiology uncertain – Glutamine synthetase?
