W6 Flashcards
What are the molecular mechanisms of neurotransmitter release?
- Budding from endosome
- connected together by synapsin
- Docking with synapsin
- Priming with NSF SNAPs then SNARES
- Influx of CA2+
- Fusion with synaptotagmin
- Budding with clathrin and dynamin
- uncoating with Hsc70-
- enter endosome
What are two toxins that affect neurotransmitter release and how do they do it?
Botulinum/tatanus toxins- cleave SNARE
Botulinum toxin - cleave SNAP
Ligand-gated ion channels
ionotrope - ligand docks on receptor, receptor opens and lets ions through.
G-protein-coupled receptors
metabotrope - Ligand docks on receptor, causes an release of g protein element inside cell. opens ion channels.
2 types of vesicles and their mode of transport.
Small molecule neurotransmitters in clear-core vesicles.
Molecules transported down microtubes from nucleus. Packed into vesicle in PST
Peptide neurotransmitters in dense-core vesicle
Peptide precursor transported down neuro
Neurotransmitters
Activating: acetylcholine, Glutamate, catecholamines, seretonin, histamine, ATP,
Inhibiting: GABA, Glycin,
Acetylcholine
Excitatory
- Important at neuromuscular junction
- Synthesised from acetyl CoA and Choline
- Removed by AChEase
- receptors: nicotinic (non-selective, ionotrope), muscarinic (metabotrope)
- effected by nicotine, fliegepilz (muscaria), and alpha-Bungarotoxin (snake)
Glutamate
Excitatory
- most common excitatory neurotransmitter
- synthesised from glutamine
- removed by transporter EAAT (excitatory amino acid transporter) in Glia cell
- receptors: NMDA, AMPA, Kainat (Na+ & K+, ionotrope)
GABA
Inhibitory -
However, in immature neuron excitatory because of different Cl- concentration in immature cell.
Receptors: GABAa/c (Cl-, ionotrope), …b (K+, metabotrope), .
- synthesised from glutamate
- removed by transporter GAT
-ionotrope receptors influenced by benzodiazepines (valium), barbiturates and alcohol
Glycine
Inhibatory not in immature cells - synthesised from serine -receptors: ionotrope Cl- - removed by glycine transporter
Biogenic Amines (Biogene Amine)
Catecholmine: dopamine, norepinephrine (noradrenalin) epinephrin (adrenalin)
Histamine
Serotonin
Biosynthesis of catecholamine.
Tyrosine hydroxylase - DOPA - Dopamine
Dopamine is associated with…
motivation, reward system, reinforcement.
It is the neurotransmitter of the neurons in the substantia nigra.
Important for corpus striatum for the coordination of movements.
Serotonin is associated with…
sleep and wakefulness, depression, anxiety.
Neuropeptides are associated with…
feelings, pain, stress
e.g. substance p, opioids, endorphins.
