L3 Monoamines

Question 1

Answer 1

(d) Transport into the presynaptic neuronal cell via high-affinity reuptake transporters.

Question 2

Answer 2

(B) Noradrenaline is synthesised from L-tyrosine.

L-tyrosine -> L-DOPA -> Dopamine -> NA -> A

Incorrect:

(A) 5-HT is synthesised from tryptophan obtained from the diet, not DA

(C) DA has characteristic anatomical distribution, limited to restricted sub-cortical regions –> SN

(D) COMT is not involved in the 5-HT synthesis pathway:

L-Tryptophan –{Tryptophan Hydroxylase}–> 5-HTP –{DOPA Decarboxylase–> 5-HT

nor is it involved in its breakdown:

5-HT –{MAO}–>5-hydroxyindole acetaldehyde–{aldehyde dehydrogenase}–>5-HIAA

Question 3

Describe two roles for noradrenaline in the central nervous system, give an example of a therapeutic drug used to modify each of these functions in CNS disease states, and explain the mechanisms of action of these drugs, including their synaptic targets and sites of action (brain regions and/or pathways) in the CNS.