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DECARBOXYLATION OF EXOGENOUS l ‐5‐HYDROXYTRYPTOPHAN AFTER DESTRUCTION OF THE CEREBRAL RAPHE SYSTEM
Author(s) -
Korf J.,
Venema K.,
Postema F.
Publication year - 1974
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.1471-4159.1974.tb06941.x
Subject(s) - aromatic l amino acid decarboxylase , decarboxylation , medicine , endocrinology , serotonin , cerebral cortex , tryptophan hydroxylase , chemistry , decarboxylase inhibitor , 5 hydroxytryptophan , tryptophan , raphe nuclei , cortex (anatomy) , lesion , free nerve ending , raphe , serotonergic , amino acid , enzyme , biochemistry , biology , pathology , neuroscience , receptor , levodopa , disease , parkinson's disease , catalysis
— l ‐5‐Hydroxytryptophan ( l ‐5‐HTP) was administered intravenously to rats (12 mg/kg) after inhibition of the peripheral aromatic l ‐amino acid decarboxylase with l ‐α‐hydrazino‐α‐methyl dopa (MK 486). The accumulation of 5‐hydroxytryptamine (5‐HT) and 5‐hydroxyindoleacetic acid in the cerebral cortex was measured 1, 2 and 4 h after injection of 5‐HTP with automated assay techniques. Besides controls two groups of rats were studied: rats after inhibition of tryptophan‐5‐hydroxylase with p ‐chlorophenylalanine (pcpa) and subjects with a chronic lesion in the area of the raphe nucleus. The net accumulation of both measured 5‐hydroxyindoles was diminished in rat cerebral cortex after degeneration of 5‐HT containing nerve endings, compared with control animals and pcpa‐treated rats. These results indicate that the formation of 5‐HT in the cerebral cortex from exogenous l ‐5‐HTP, after inhibition of the peripheral aromatic amino acid decarboxylase, occurs predominantly in 5‐HT containing nerve endings possibly by a specific 5‐HTP‐decarboxylating enzyme.