title: Rhodiola-water extract induces β-endorphin secretion to lower blood pressure in spontaneously hypertensive rats.
abstract: Rhodiola rosea (Rhodiola) is grown at high altitudes and northern latitudes. It is mainly used clinically as an adaptogen, but antihypertensive effects have been reported for the extract. These have not been well investigated, so in the present study, we evaluated the effect of Rhodiola-water extract on blood pressure in spontaneously hypertensive rats (SHRs) and investigated the potential mechanism(s) for this action. In conscious male SHRs, systolic blood pressure (SBP) and heart rate were recorded using the tail-cuff method. Plasma β-endorphin was measured by enzyme-linked immunosorbent assay. Rhodiola-water extract decreased SBP in SHRs in a dose-dependent manner, and this action was more significant than that in normal group named Wistar-Kyoto (WKY) rats. This reduction of SBP in SHRs was inhibited by pretreatment with the selective opioid μ-receptor antagonist, cyprodime, but not by naloxonazine, an antagonist specific to opioid μ1-receptor. Also, the SBP-lowering action of Rhodiola-water extract was attenuated in adrenalectomized SHRs. Moreover, Rhodiola-water extract dose-dependently increased β-endorphin release in SHRs, and the elevation of β-endorphin in SHRs was higher than that in WKY. Thus, we suggest that Rhodiola-water extract can induce release of β-endorphin to lower SBP in SHRs.
authors.affiliation: Department of Emergency Medicine, Chi-Mei Medical Center, Yong Kang, Tainan City, 73101, Taiwan.
authors.forename: Wei-Jing
authors.initials: WJ
authors.lastname: Lee
authors.forename: Hsien-Hui
authors.initials: HH
authors.lastname: Chung
authors.forename: Yung-Ze
authors.initials: YZ
authors.lastname: Cheng
authors.forename: Hung Jung
authors.initials: HJ
authors.lastname: Lin
authors.forename: Juei-Tang
authors.initials: JT
authors.lastname: Cheng
mesh_terms: D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D009019:Morphinans / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D029771:Rhodiola / Q000737:chemistry*; D001615:beta-Endorphin / Q000097:blood*
chemical_list: D000959:Antihypertensive Agents; D009019:Morphinans; D010936:Plant Extracts; C058450:cyprodime; D001615:beta-Endorphin