Neurotransmitters II Flashcards
What is ChAT (choline acetyltransferase) used for?
Synthesis of ACh
Where are ACh synapses found?
nmj, CNS, frontal cortex of brain
What are ACh synapses in the brain important for?
Executive function, memory
What is ACh synthesised from?
Acetyl-CoA and choline
Where is the coline for ACh from?
Serum derived–> comes from periphery
Difference between ACh and other NTs?
ACh needs peripheral delivery of choline, other NTs have their components more central
Which two receptor subtypes can ACh act on?
Nicotinic receptor and muscarinic receptor
Nicotinic receptor type?
Gated ion channels
Muscarinic receptor type?
G-protein coupled (slower)
Role of acetylcholinesterase?
ACh degradation
What happens to choline following ACh degradation?
Retransported into nerve terminalWh
What is ACh broken down into?
Choline and acetate
What is the major target for presymptomatic AZ treatments?
AChE–> inhibited to maintain cholinergic transmission
WHat is glutamate converted from?
Glutamine
Glutamine to glutamate enzyme?
Glutaminase
Where is glutaminase found?
Mitochondrial membrane
Where is the NT glutamate specifically converted from?
GLutamine using glutaminase on mitochondrial membranes
Glutamate termination mechanism?
Reuptake
Where can glutamate receptors be?
Postsynaptic, nerve terminal (autoreceptor), astrocytes (neighbouring cells)
Where can glutamate reuptake transporters be?
Nerve terminals, glial cells, extrasynaptic
Role of extrasynaptic glutamate transporters?
Prevent the transmitter from diffusing out of the synapse and affecting neighboring cells
Effect of too high glutamate conc?
Neurotoxicity
What happens to glutamate after it is reuptaken?
Converted into glutamine
Why is glutamate converted to glutamine before being transported back into the nerve terminal?
Glutamine is much less toxic
Glutamate glutamine shuttle?
GLutamate is taken up by astrocytes, converted to glutamine and then moved into nerve terminals
Role of glutathione?
Antioxidant in the brain
How does glutathione work?
It is a free radical, and protects from other free radical damage
What does a nerve terminal have to have in order to be GABAergic?
Glutamic acid decarboxylase (GAD_
Role of GAD?
Conversion of glutamate to GABA
How is GABA termianted?
Via GAT transporters
