Neurotransmitters I, synthesis storage and degradation Flashcards
When was it discovered that there were breaks (synapses) in the nervous system and that it wasn’t a syncitium?
1888-1934
Fist small molecule transmitter to be identified?
ACh
How was ACh discovered?
Took a isolated frogs heart w/ vagus nerve intact
If stimulated nerve could influence muscle contraction in the heart
Could transfer solution of stimulated heart to a heart that didnt have a vagus nerve, could mimic the change in muscle contraction and heart rate
What did Otto Loewi show?
The nerve was releasing smthn soluble that was involved in heart stimulation
Axodendritic synapse?
Axon onto dendrite
Neuromuscular synapse?
Neuron onto muscle cell/peripheral tissue
Basic signalling sequence?
Presynaptic AP Depolarisation of synaptic terminal Release of chemical transmitter Postsynaptic signal
What are most chemical transmitters in the mammalian nervous system derived from?
AAs
Why is there a v strong link between neurotransmission and cellular metabolism?
Lots of NTs are synthesised via metabolism–> i.e. AAs
How many NTs can a given synapse use?
1
Diff types of synapse?
Glutamatergic, GABAergic, cholinergic, noradrenergic, dopaminergic, serotonergic
Why does the NT a synapse uses define it?
Synapses can only use one NT
Which signalling molecules can a synapse use more than one of?
Neuropeptides
WHich small molecule transmitter is a purine?
ATP
Subdivision of biogenic amine NTS?
Catecholamines, indoleamine, imidazoleamine
What are the catecholamines?
Dopamine, norepinephrine, epinephrine
What is the indoleamine?
5HT
What is the imidazoleamine?
Histamine
What are the AA small molecule transmitters?
Glutamate, aspartate, GABA
What are the catecholamines derived from?
Tyrosine
What is 5HT derived from?
Tryptophan
Criteria to be a small molecule transmitter?
Enzymes 4 synthesis present in nerve terminal
Storage in secretory vesicles
Release into synapse
Reception–> receptors
Removal–> terminating action
Life cycle of a transmitter?
- Synthesis
- Storage/ Packaging
3.Regulated Release
4.Detection/ Signalling - Reuptake/ Degradation
Where can transmitter receptors be?
Postsynaptic, presynaptic, on neighbouring cells
Ways of removing transmitter from synapse?
Reuptake by neighbouring/Pre N cells
Degradation in the synapse
Where are transmitter degradation enzymes?
Tethered to membranes w/ lipid anchors
How is glutamate packaged into vesicles?
Proton driven active transporters
Why are active transporters needed to package glutamate into vesicles?
Need to drive the transmitter against conc grad to fill vesicle w/ a high enough conc of transmitter
Glutamate transporter on vesicular membrane name?
VGluT (vesicular glutamate transporter
Relationship between vesicular glutamate transporter and glutamate reuptake transporter?
Structurally unrelated
