In which of the following disease decrease in levels of single neurotransmitter was first identified?

Ans. b. Parkinson's disease 'The systematic biochemical investigation of the brains of patients with Alzheimer's disease began in the late 1960s and early 1970s. The hope was that a clearly defined neurochemical abnormality would be identified, providing the basis for the development of rational therapeutic interventions analogous to levodopa treatment of Parkinson's disease. '- http:// www.ncbi.nlm.nih.gov/pmc/ aicles/PMC1736202/pdf/v066p00137.pdf 'Schizophrenia is due to dysregulated serotonin, dopamine and noradrenaline, but a predominant role of a single neurotransmitter has not been described yet Disease Related Neurotransmitter/Pathology Schizophrenia Dopamine, Serotonin and Norepinephrine are Ted Huntington's disease CAG trinucleotide expansiondeg on a gene called 'Huntingtin' localized on chromosome 4Q. Caused by triple repeat expansion mutationQ Parkinson's disease Degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNc),reduced striatal dopamine, and intracytoplasmic proteinaceous inclusions known as Lewy bodies Alzheimer's disease Biochemically, AD is associated with a decrease in the coical levels of several proteins and neurotransmitters, especially acetylcholine, its synthetic enzyme choline acetyltransferase, and nicotinic cholinergic receptors.