Neurotransmitter and brain pathways L4 Flashcards
criteria to be a neurotransmitter
- must be synthesised or present in presynaptic neurone
- must produce response in postsynaptic membrane
- must be a mechanism for removal
2 main subdivisions of neurotransmitter
Small molecule neurotransmitter
neuropeptide
type of vesicles small molecules are transported in
small clear vesicles
type of vesicles neuropeptides are transported in
large dense core vesicles
what do small molecules transmit
fast transmission
what do neuropeptides transmit
slow synaptic signalling
which formation is faster for neurotransmitter
neuropeptide
cholinergic neurons=
acetylcholine
Glutamatergic neurone=
Glutamate
GABAergic neurones=
GABA
Catecholaminergic neurones=
noradrenaline
adrenaline
dopamine
serotonergic neurones=
serotonin
peptidergic neurones=
peptides
2 types of receptor
ionotropic receptors
metabotropic receptor
what are ionotropic receptors
the receptor has an ion channel and binding NT leads to opening (fast transmission)
what are mechanotropic receptors
receptors coupled to transmembrane protein leads to an effect within the cell
most common NT in PNS=
acetylcholine
what receptors does acetyl choline act on
nicotinic and muscarinic
what can death of cholinergic neurons in the forebrain cause
Alzheimer’s disease
how to treat alzheimer’s
ACHE (acetylcholineesterase) inhibitor
what enzyme synthesises Acetyl choline synthesis
ChAT (choline acetyltransferase)
3 amino acid neurotransmitters
Glutamate, GABA and glycine
main excitatory neurone in the brain=
Glutamate
what is glutamate broken down into
glutamine
what converts glutamine to glutamate
Glutaminase
how is glutamine removed from the synaptic cleft
glutamate transporters on presynaptic transporters and gilia cells
what can happen if you lack glutamate transporters
motor neurone disease, epilepsy and Alzheimer’s disease
3 main glutamate receptors
AMPA
NMDA
Kainate
what can antagonising AMPA and NMDA treat
epilepsy
main inhibitory neurotransmitters in the CNS (2)
GABA
Glycine
what is the precursor for GABA
Glutamate
what coverts Glutamate to GABA
GAD (glutamic acid decarboxylase)
what resorbs GABA/ Glycine
Transporters found on glial cells and presynaptic neurons
2 type of GABA receptors
GABA-A
GABA-B
what can agonising GABA receptors treat
Epilepsy
e.g of GABA agonist
Diazepam
what drug can increase GABA in the brain
sodium valproate
how does GABA work
it hyperpolarises the cell
Glycine synthesis=
serine which is converted to glycine
how is glycine reabsorbed
by glial cells on presynaptic neurone
where is serine derived from
Glucose
glycine main role
major spinal cord/ brainstem inhibitory Neurotransmitter
name 3 biogenic amines
Noradrenaline
adrenaline
dopamine
what is the main precursor for biogenic amines
Tyrosine
what can tyrosine be converted into
L-dopa
What coverts L-dopa into dopamine
dopa decarboxylase
what can dopamine be converted into
Adrenaline and noradrenaline
what breaks down Biogenic amines (2)
MAOa
MAOb
what does MAOa break down (oxidises)
serotonin and NE
What does MAOb breakdown (oxidises)
dopamine
3 dopamine systems in the brain
Mesolimbic
Mesocortical
Nigrostriatal
2 dopamine receptors
D1
D2
what does D1 receptors include
D1 and D5
what does D2 receptors include
D3 and D4
where is Noradrenaline found
locus coeruleus
what does Noradrenaline play a role in the brain in
sleep, attention and feeding
decreased Noradrenaline—>
depression
increased Noradrenaline—>
Mania
what is serotonin synthesised from
tryptophan (meet and diary)
where is serotonin found
Raphe nuclei
serotonin plays a role in
mood, emotions and sleep
how is serotonin stored in vesicles
same monoamine transporter VMAT as catecholamines
how is serotonin reabsorbed
SERT (serotonin transporter)
how is serotonin broken down
by MAO
what can serotonin be metabolised to become
melatonin
what are drugs called that inhibit SERT
SSRIs
E.g of a SSRI
Escitalopram