title: Simultaneous measurement of tyrosine, tryptophan and related monoamines for determination of neurotransmitter turnover in discrete rat brain regions by liquid chromatography with electrochemical detection.
abstract: Concomitant measurement of monoamine neurotransmitter turnover in discrete rat brain areas with the use of radiolabeled amino acid precursors permits simultaneous evaluation of interacting transmitter systems. [3H]Tyrosine and [3H]tryptophan were administered via indwelling catheters to unrestrained rats. Content and specific activity of norepinephrine, dopamine, 5-hydroxytryptamine, and the metabolites dihydroxyphenylacetic acid, homovanillic acid, and 5-hydroxyindoleacetic acid in addition to tyrosine and tryptophan were quantified by liquid chromatography with electrochemical detection and liquid scintillation counting. The method employs a simple extraction procedure without prior cleanup for chromatography. Neurotransmitter turnover rates that incorporated tyrosine- or tryptophan-specific activities were found to be two to four times greater than those that did not include them.
mesh_terms: D000818:Animals; D001679:Biogenic Amines / Q000032:analysis*; D001923:Brain Chemistry; D002853:Chromatography, Liquid / Q000379:methods; D004563:Electrochemistry; D008297:Male; D018377:Neurotransmitter Agents / Q000032:analysis*; D051381:Rats; D012701:Serotonin / Q000032:analysis; D014364:Tryptophan / Q000032:analysis*; D014443:Tyrosine / Q000032:analysis*
chemical_list: D001679:Biogenic Amines; D018377:Neurotransmitter Agents; D012701:Serotonin; D014443:Tyrosine; D014364:Tryptophan