Open AccessOrexin A promotes histamine, but not norepinephrine or serotonin, release in frontal cortex of mice 1
Author(s) -
HONG Zongyuan,
HUANG Zhili,
QU Weimin,
EGUCHI Naomi
Publication year - 2005
Publication title -
acta pharmacologica sinica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.514
H-Index - 90
eISSN - 1745-7254
pISSN - 1671-4083
DOI - 10.1111/j.1745-7254.2005.00523.x
Subject(s) - histamine , serotonin , microdialysis , endocrinology , medicine , orexin , norepinephrine , orexin a , chemistry , catecholamine , neurotransmitter , histamine h3 receptor , dopamine , biology , neuropeptide , central nervous system , receptor , antagonist
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.