[Campbell Biology P.1153] Why is L-dopa used to treat Parkinson's disease instead of directly... | Practice Question

Why is L-dopa used to treat Parkinson's disease instead of directly administering dopamine, according to the text and diagram?

  • A: L-dopa is more effective at reducing muscle tremors directly.
  • B: Dopamine cannot cross the blood-brain barrier, but L-dopa can.
  • C: L-dopa prevents the breakdown of existing dopamine in the brain.
  • D: The enzyme dopa decarboxylase is inhibited by dopamine but activated by L-dopa.

Explanation

The text states: 'Unlike dopamine, L-dopa crosses the blood-brain barrier. Within the brain, the enzyme dopa decarboxylase converts the drug to dopamine, reducing the severity of Parkinson's disease symptoms'.