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Serotonin release varies with brain tryptophan levelsThis study examines directly the effects on serotonin release of varying brain tryptophan levels within the physiologic range. It also addresses possible interactions between tryptophan availability and the frequency of membrane depolarization in controlling serotonin release. We demonstrate that reducing tryptophan levels in rat hypothalamic slices (by superfusing them with medium supplemented with 100 microM leucine) decreases tissue serotonin levels as well as both the spontaneous and the electrically-evoked serotonin release. Conversely, elevating tissue tryptophan levels (by superfusing slices with medium supplemented with 2 microM tryptophan) increases both the tissue serotonin levels and the serotonin release. Serotonin release was found to be affected independently by the tryptophan availability and the frequency of electrical field-stimulation (1-5 Hz), since increasing both variables produced nearly additive increases in release. These observations demonstrate for the first time that both precursor-dependent elevations and reductions in brain serotonin levels produce proportionate changes in serotonin release, and that the magnitude of the tryptophan effect is unrelated to neuronal firing frequency. The data support the hypothesis that serotonin release is proportionate to intracellular serotonin levels.
Document ID
19930048122
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Schaechter, Judith D.
(NASA Headquarters Washington, DC United States)
Wurtman, Richard J.
(MIT Cambridge, MA, United States)
Date Acquired
August 16, 2013
Publication Date
January 1, 1990
Publication Information
Publication: Brain Research
ISSN: 0006-8993
Subject Category
Life Sciences (General)
Accession Number
93A32119
Funding Number(s)
CONTRACT_GRANT: NIH-T32-MH-19761-0851
Distribution Limits
Public
Copyright
Other

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