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Calcium‐Dependent, Tetrodotoxin‐Sensitive Stimulation of Cortical Serotonin Release After a Tryptophan Load
Author(s) -
Carboni E.,
Cadoni C.,
Tanda G. L.,
Chiara G.
Publication year - 1989
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.1471-4159.1989.tb11802.x
Subject(s) - tryptophan , serotonin , tetrodotoxin , chemistry , microdialysis , 5 hydroxyindoleacetic acid , perfusion , stimulation , dialysis tubing , extracellular , cortex (anatomy) , medicine , 5 ht receptor , endocrinology , chromatography , biochemistry , biology , amino acid , receptor , neuroscience , membrane
The effect of intraperitoneal administration of tryptophan (50, 100, or 200 mg/kg) on extracellular concentrations of tryptophan, serotonin (5‐hydroxytryptamine, 5‐HT), and 5‐hydroxyindoleacetic acid (5‐HIAA) was studied in the cortex of freely moving rats by transcerebral dialysis. Rats were implanted with dialysis probes in the frontal cortex, and experiments were performed 24 h later. Tryptophan, 5‐HT, and 5‐HIAA were quantified in 20‐min samples of dialysate by HPLC with electrochemical detection after separation on reverse‐phase columns. Tryptophan administration resulted in a significant increase of tryptophan, 5‐HT, and 5‐HIAA levels in di‐alysates. The maximal increase of 5‐HT and 5‐HIAA output was ˜ 150% over basal values. Perfusion with Ringer's solution containing tetrodotoxin (1 μ M ) reduced 5‐HT output by 90% and prevented the increase of 5‐HT and 5‐HIAA content after 100 mg/kg of tryptophan. Similar results were obtained after perfusion with Ringer's solution without Ca 2+ . The results indicate that a tryptophan load stimulates the physiological release of 5‐HT.