4. Noradrenergic Transmission

Question 0

α-methyldopa

Answer 0

Taken up into noradrenergic terminals, converted to methyl dopamine and methylnoradrenaline
Methylnoradrenaline is a false transmitter, stored in vesicles and released
Acts weakly on a1 receptors but more strongly at a2-> antihypertensive

Question 1

Carbidopa

Answer 1

Peripheral inhibitor of dopa decarboxylase thus preventing dopa breakdown outside the cns
Reduces peripheral side effects of l-dopa

Question 2

Reserpine

Answer 2

Binds the amine binding site of the vesicular mono amine transporter (VMAT2)
Vesicles are leaky and neurotransmitter is depleted and degraded by MAO
Mainly acts in periphery of brain, previous use as antihypertensive but major depressive side effects

Question 3

Tyramine

Answer 3

Indirectly acting sympathomimetic amine
Found in cheese, red wines, marmite, etc
Uptake 1-> Displaces NA from vesicles -> some NA escapes MAO -> NA reaches post synaptic adrenoreceptors

Question 4

Guanethidine

Answer 4

Blocks NA release

1) compete with NA for entry via uptake 1
2) behaves as an indirect sympatheticomimetic amine in large doses
3) block vesicle release following an AP

Question 5

Cocaine

Answer 5

Blocks uptake 1 (NET/SLC6A2)

Increases duration for which catecholamines are active

Question 6

Imaprimine

Answer 6

Tricyclic antidepressant

Blocks uptake 1 (NET/SLC6A2) for noradrenaline and 5-HT

Question 7

Amitryptyline

Answer 7

Tricyclic antidepressant

Blocks uptake 1 (NET/SLC6A2) for noradrenaline and 5-HT