color pdf

BIMM118
Dopamine replacement:
Parkinson’s Disease
Dopamine does not cross blood-brain barrier => use of
• Levodopa (L-Dopa)
– Metabolic precursor of dopamine
– High concentrations required, as most of L-Dopa is decarboxylated in the
periphery => high concentration of peripheral dopamine => side effects!
– L-Dopa combined with
• Carbidopa
– L-Dopa decarboxylase - inhibitor
– Does not cross blood-brain barrier =>
only peripheral effect => increases the amount
of L-Dopa that reaches the brain