MR S10 - Incomplete Flashcards Preview

ESA2 > MR S10 - Incomplete > Flashcards

Flashcards in MR S10 - Incomplete Deck (6)
Loading flashcards...
1

Describe the storage of ACh

Actively packaged into high concentration (>100mM) vesicles at cholinergic terminals

2

Describe the termination of ACh

Acetylcholine esterase degrades ACh to choline and acetate
In fast/nicotinic synapses, the enzyme is faster so half life of ACh is only a few milliseconds
A choline channel on the terminal of the synapse recaptures most choline

3

Describe the synthesis of noradrenaline

Tyrosine is converted to DOPA by tyrosine hydroxylase (which is the rate-limiting step)
DOPA is converted to dopamine by aromatic amino acid decarboxylase (which is then packaged in a vesicle)
Dopamine is converted to noradrenaline by dopamine β hydroxylase (this occurs within the vesicle)

4

Describe the packaging of noradrenaline

Active transport required to package dopamine into a vesicle, where it is converted to NA
High-concentration vesicle (0.5-1.0M)

5

Describe the termination of noradrenaline

Uptake 1 is a high affinity reuptake system which removes NA from the synaptic cleft into cells
Uptake 2 is a widespread, lower affinity reuptake system which removes NA from the extracellular space
Cytoplasmic NA may be broken down by mono amine oxidase (MOA)

6

Describe the synthesis of ACh

ACh is synthesised from acetyl CoA and choline by the enzyme choline acetyltransferase in the cytoplasm of cholinergic terminals