chemicals in the brain Flashcards
(38 cards)
What is the role of synapsin
Anchors a pool of vesicles to the cytoskeleton
Outline synaptic vesicle release and recycling
after an AP, Voltage-gated Ca2+ channels open and calcium ions flow into the cytoplasm and activates calcium m calmodulin activated kinase 2 (caMKII) which phosphorylates synapsin. p-synapsin can no longer bind to the cytoskeleton, vesicles dock to the active zone.
What is a SNARE complex
They dock vesicles to the plasma membrane
Outline the mechanism of exocytosis
The vesicle docks and calcium is released once the AP arrives, the SNARE complexes are formed which pulls the two membranes together and allows the vesicle ot empty its contents into the synaptic cleft.
What are two important proteins on vesicles that aid in exocytosis
synaptobrevin and synaptotagmin
What are two important proteins on the terminal end of exocytosis
Syntaxin and SNAP-25
What is a property of botox and tetanus
They can prevent neurotransmitter release
What are the categories of neurotransmitters
Amino acids, Monoamines, acetylcholine and neuropeptides.
Where are neuropeptides synthesised, stored and what are they released in response to
They are synthesised in the cell soma and transported to the terminal, stored in secretory granules and released in response to global increase in calcium ions.
Give an example of a fast neurotransmitter
amino acid
give an example of a slow neurotransmitter
neuropeptides
How are fast NM categorised
excitator: glutamate and inhibitory: GABA in the brain and Glycine in the spinal cord and brainstem
How do excitatory NM work
They slightly depolarise the post synaptic cells membrane
How do inhibitory NM work
They slightly hyperpolarise the post synaptic cells membrane
Outline the functions of the seteronergic system
function in: mood, sleep, pain, emotion and appetite
Where is glutamate synthesised
At the presynaptic source either from glucose via the krebs cycle or from glutamine converted to glutaminase into glutamate
Where is glutamate stored
Loaded and stored in vesicles by vesicular glutamate transporters (VGLUT’s)
How is glutamate reuptaked
Reuptake by excitatory amino acid transporters (EAATs) in the plasma membrane of the presynaptic cell and surrounding glial cells.
What is the role of glial cells in the reuptake of glutamine
They convert glu to glutamine and this is transported from the glia back to nerve terminals where it is converted back into glutamate
Where is GABA synthesised
Synthesised from glutamate in a reaction catalysed by glutamic acid decarboxylase (GAD)
Where is GABA stored
loaded and stored into vesicles by vesicular GABA transporter
How is GABA cleared from the synapse
reuptake via transporters on glia and neurons
What is a result of too much GLU with too little GABA
hyper-excitability which can lead to epilepsy
What can too much GABA result in
Sedation/ Coma
