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.
Orexin A promotes histamine, but not norepinephrine or serotonin, release in frontal cortex of mice1
Article first published online: 27 JAN 2005
Acta Pharmacologica Sinica
Volume 26, Issue 2, pages 155–159, February 2005
How to Cite
HONG, Z.-y., HUANG, Z.-l., QU, W.-m. and EGUCHI, N. (2005), Orexin A promotes histamine, but not norepinephrine or serotonin, release in frontal cortex of mice. Acta Pharmacologica Sinica, 26: 155–159. doi: 10.1111/j.1745-7254.2005.00523.x
- Issue published online: 27 JAN 2005
- Article first published online: 27 JAN 2005
- Received 2004-09-13; Accepted 2004-10-28
- orexin A;
- frontal cortex
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.