Parkinson's disease is characterized by dopamine depletion in the substantia nigra, treated with L-DOPA, a dopamine precursor that crosses the blood-brain barrier.

“so dopamine is also really important for movement as you know Parkinson's disease which is a movement disorder is characterized by a decrease or a depletion of dopamine in a different part of the brain called the substantia um and one of the ways that we treat Parkinson's is to actually give people L Doopa which is a dopamine precursor why do we give them L Doopa and not dopamine because do itself actually can't cross the bloodb brain barrier so we give them a precursor that crosses the blood brain barrier and then um you know binds to doine receptors in the substanti allowing for more fluid movements in people with Parkinson's”