Dopamine is a neurotransmitter involved in the reward pathways in the brain, and its decreased activity has been associated with diseases such as Parkinson's disease and attention-deficit/hyperactivity disorder (ADHD). Which of the following drugs is NOT a likely candidate to treat these diseases?

A) Methylphenidate, a dopamine reuptake inhibitor
B) Amphetamine, a dopamine-releasing agent that triggers the release of dopamine into the synaptic cleft
C) Carbidopa, which enhances the availability of the dopamine synthesis precursors in the brain
D) Forskolin, a sensitizer of dopamine receptors
E) Chlorpromazine, a dopamine antagonist that binds to and inhibits dopamine receptors