Orexin A promotes histamine, but not norepinephrine or serotonin, release in frontal cortex of mice1

Authors

  • Zong-yuan HONG,

    1. School of Life Science, University of Science and Technology of China, Hefei 230027, China;
    2. Department of Molecular Behavioral Biology, Osaka Bioscience Institute, Furuedai, Suita, Osaka 565-0874, Japan;
    Search for more papers by this author
  • Zhi-li HUANG,

    Corresponding author
    1. Department of Molecular Behavioral Biology, Osaka Bioscience Institute, Furuedai, Suita, Osaka 565-0874, Japan;
    2. Department of Pharmacology, Shanghai Medical College of Fudan University, Shanghai 200032, China
    Search for more papers by this author
  • Wei-min QU,

    1. Department of Molecular Behavioral Biology, Osaka Bioscience Institute, Furuedai, Suita, Osaka 565-0874, Japan;
    Search for more papers by this author
  • Naomi EGUCHI

    1. Department of Molecular Behavioral Biology, Osaka Bioscience Institute, Furuedai, Suita, Osaka 565-0874, Japan;
    Search for more papers by this author

  • 1

    Project supported in part by a grant-in-aid for scientific research from the Japan Society for the Promotion of Science (ZLH) and Osaka City.

Correspondence to Zhi-li HUANG, MD, PhD.
Phn 81-6-6872-4851.
Fax 81-6-6872-2841.
E-mail huangzl@obi.or.jp

Abstract

Aim: To investigate the effects of orexin A on release of histamine, norepinephrine, and serotonin in the frontal cortex of mice.

Methods: Samples for measuring histamine, norepinephrine, and serotonin contents were collected by in vivo microdialysis of the frontal cortex of anesthetized mice. The histamine, noradrenaline, and serotonin content in dialysates were measured by HPLC techniques.

Results: Intracrebroventricular injection of orexin A at doses of 12.5, 50, and 200 pmol per mouse promoted histamine release from the frontal cortex in a dose-dependent manner. At the highest dose given, 200 pmol, orexin A significantly induced histamine release, with the maximal magnitude being 230% over the mean basal release. The enhanced histamine release was sustained for 140 min, and then gradually returned to the basal level. However, no change in norepinephrine or serotonin release was observed under application of the same dose of orexin A.

Conclusion: These results suggest that the arousal effect of orexin A is mainly mediated by histamine, not by norepinephrine or serotonin.

Ancillary