Neurotransmitter depleted in Parkinson's disease:September 2007

Ans. A: DopamineParkinson's disease has both hypokinetic and hyperkinetic features. In this condition, which was originally described by James Parkinson and is named for him, the nigrostriatal dopaminergic neurons degenerate. The fibers to the putamen are most severely affected.Dopaminergic neurons and dopamine receptors are steadily lost with age in the basal ganglia in normal individuals, and an acceleration of these losses apparently precipitates parkinsonism. Symptoms appear when 60-80% of the nigrostriatal dopaminergic neurons are lost. Parkinsonism is also seen as a complication of treatment with the phenothiazine group of tranquilizer drugs and other drugs that block D2 dopamine receptors.