skip to main content

L-DOPA Crosses BBB — FRCA Primary MCQ

Instant feedback + full explanation. One question, done properly.

ModeratePhysiology - NeurophysiologyL-DOPA Crosses BBBFRCA Primary

Regarding the blood-brain barrier which neurotransmitter precursor can cross the BBB?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: DL-DOPA (levodopa)

L-DOPA (the precursor of dopamine) crosses the BBB via the large neutral amino acid transporter. Dopamine itself cannot cross the BBB which is why it is ineffective for treating Parkinson's disease when given peripherally. L-DOPA is given with a peripheral decarboxylase inhibitor (carbidopa/benserazide) to prevent peripheral conversion and maximise CNS delivery.

Reference: Power Kam 2018 Principles of Physiology for the Anaesthetist