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AMINE FORMATION FROM l ‐TRYPTOPHAN IN BRAIN SLICES
Author(s) -
WeilMalherbe H.
Publication year - 1976
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1976.tb05142.x
Subject(s) - tryptamine , serotonin , striatum , pons , hypothalamus , tryptophan , chemistry , pargyline , cortex (anatomy) , endocrinology , medicine , tryptophan hydroxylase , reticular formation , cerebral cortex , medulla , biology , biochemistry , stimulation , dopamine , neuroscience , serotonergic , amino acid , receptor
— Slices from four areas of guinea‐pig brain (hypothalamus, corpus striatum, median ponsmedulla and cerebral cortex) were incubated with concentrations of l ‐[3‐ 14 C]tryptophan varying from 20 to 300 μ m . in the presence of 5 × 10 ‐5 m ‐pargyline. The formation of tryptamine and serotonin was studied. Serotonin synthesis reached its highest level at a concentration of approx 80 μ m ‐tryptophan in all 4 brain areas. Activity was high in pons‐medulla and hypothalamus but only about one third as high in corpus striatum and cortex. Tryptamine formation continued to increase within the concentration range of tryptophan used. Activity was high in corpus striatum where, at 300 μ m ‐tryptophan, tryptamine formation exceeded serotonin formation, but was low in cortex and intermediate in pons‐medulla and hypothalamus. The possible formation of kynuramine and 5‐hydroxykynuramine was also investigated. No evidence was obtained for the formation of 5‐hydroxykynuramine. Traces of radioactivity were found corresponding to kynuramine, but these were insufficient to establish its formation with certainty. If formed. the rate of kynuramine synthesis did not exceed 2% of the combined formation of serotonin and tryptamine.