Pharmacology of basal ganglia disorders

Question 1

Why does levodopa need to be given as a precursor to dopamine, rather than a synthetic form of dopamine?

Answer 1

Dopamine cannot cross the blood brain barrier, whereas levodopa can

Question 2

Which 3 enzymes can break down dopamine?

Answer 2

DDC
COMT
MAO-B

Question 3

Why is nausea a common side effect of levodopa?

Answer 3

Dopamine activates the chemoreceptor trigger zone (CTZ) in the area postrema (vomiting centre)

Question 4

Of the enzymes that can break down dopamine, which one is intracellular?

Answer 4

MAO-B

Question 5

Of the enzymes that can break down dopamine, which one breaks it down in the CNS as opposed to the periphery?

Answer 5

MAO-B