Cardiovascular effect of intracerebroventricular injection of orexin-1 receptor antagonist in rats.
- Author:
Bao-Qiang GUO
1
;
Min JIA
;
Jin-Xu LIU
;
Zhao ZHANG
Author Information
- Publication Type:Journal Article
- MeSH: Animals; Blood Pressure; drug effects; Heart Rate; drug effects; Male; Orexin Receptors; Phenylurea Compounds; administration & dosage; pharmacology; Rats; Rats, Sprague-Dawley; Receptors, G-Protein-Coupled; antagonists & inhibitors; Receptors, Neuropeptide; antagonists & inhibitors
- From: Chinese Journal of Applied Physiology 2010;26(3):278-283
- CountryChina
- Language:Chinese
-
Abstract:
OBJECTIVETo study the cardiovascular effect of selective orexin-1 receptor (OX1R) antagonist SB408124 in anesthetized rats and explore the underlying mechanism by using intracerebroventricular (ICV) microinjection combined with immunohistochemical assay.
METHODSThe changes of mean arterial blood pressure (MAP) and heart rate (HR) of male Sprague-Dawley rats were recorded during ICV microinjection of SB408124 with or without pretreatment of atropine methyl nitrate or hexamethonium bromide. Furthermore, tyrosine hydroxylase (TH) immunopositive neurons in the rostral ventrolateral medulla (RVLM) of the rat were detected with immunohistochemical assay after ICV microinjection of SB408124.
RESULTSICV administration of SB408124 resulted in a significant decrease in MAP in anesthetized rats, which was accompanied with a mild decrease in HR. The cardiovascular responses elicited by SB408124 were not abolished by pretreatment of atropine methyl nitrate whereas fully abolished by pretreatment of hexamethonium bromide. The number of TH-immunopositive neurons in rat RVLM were significantly decreased following ICV administration of SB408124.
CONCLUSIONICV microinjection of selective OX1R antagonist SB408124 can cause decreases of MAP and HR mediated by inhibiting sympathetic activity in anesthetized rats.
