title: Determination of tyrosine, tryptophan and their metabolic derivatives by liquid chromatography-electrochemical detection: application to post mortem samples from patients with Parkinson's and Alzheimer's disease.
abstract: A procedure is described for the rapid determination of the major indoles and catechols. Analysis with picogram detection limits was done by high-pressure liquid chromatography on a C18 reverse-phase column using electrochemical detection (LCEC). This method provides a comprehensive list of compounds which can be simultaneously determined in brain samples and for which there is no necessity of derivatization or pre-column purification. The regional distribution of 9 neurochemicals from rat brain and the levels of 10 neurochemicals from human brain are presented. DOPA, TYR, NE, MHPG, DOPAC, 5-HIAA, TRP, DA, HVA, 3-MT and 5-HT were detected in the caudate nucleus and putamen. The levels of neurochemicals from the caudate and putamen of a demented patient with Parkinson's disease were variably decreased; catechol and indole losses were greatest in the putamen. The levels of neurochemicals in the caudate and putamen of patients with Alzheimer's disease (SDAT) were also variably decreased; loss of NE was seen only in putamen and losses of DA, HVA and 5-HT were uniform across both caudate and putamen. The CSF of SDAT patients showed changes in NE only.
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000378:metabolism*; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004563:Electrochemistry; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000378:metabolism*; D051381:Rats; D014364:Tryptophan / Q000032:analysis*; D014443:Tyrosine / Q000032:analysis*
chemical_list: D014443:Tyrosine; D014364:Tryptophan