In vivo measurement of hypothalamic serotonin release by intracerebral microdialysis: Significant enhancement by immobilization stress in rats

Nobuaki Shimizu, Sachiko Take, Tetsuro Hori, Yutaka Oomura

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101 Citations (Scopus)

Abstract

Intracerebral microdialysis was used to measure extracellular serotonin and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) in the hypothalamus of unanesthetized rats. Increase in the concentration of K+ in the perfusing Ringer solution (70 mM) produced a sharp increase in serotonin release, which was significantly attenuated by omitting Ca2+ from the perfusion medium. Intraperitoneal injection of 5-hydroxytryptophan, a precursor of serotonin, or local perfusion of pargyline, a monoamine oxidase inhibitor, elevated the hypothalamic serotonin. Releasers or uptake inhibitors of serotonin, such as fenfluramine, cocaine, mazindol, or imipramine, when added to the perfusion medium, significantly increased serotonin level, whereas 5-HIAA was unaffected by these substances. Immobilization-stress caused an immediate increase in both the extracellular serotonin and 5-HIAA in the hypothalamus, suggesting that the hypothalamic serotonergic system is activated during immobilization stress. The present study indicates that the brain microdialysis is useful for analysis of local changes in serotonin concentration which directly reflect neuronal transmission.

Original languageEnglish
Pages (from-to)727-734
Number of pages8
JournalBrain Research Bulletin
Volume28
Issue number5
DOIs
Publication statusPublished - May 1992

All Science Journal Classification (ASJC) codes

  • Neuroscience(all)

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