[Hypersensitization of alpha-adrenoreceptor of artery smooth muscle in hypertensive rats and hypertensive patients].
OBJECTIVE
To investigate the hypersensitization of alpha-adrenoreceptor of artery smooth muscle in hypertensive patients and rats and the mechanisms concerned.


METHODS
Isometric tension of artery ring segments was recorded by a sensitive myograph system in vitro and the relative amount of alpha-adrenoreceptor mRNA was quantified by a real-time PCR.


RESULTS
Noradrenaline (NA)-induced concentration-contraction curve of mesenteric artery segments in spontaneously hypertensive rats (SHR) was more potent than that in Wistar-Kyoto (WKY) rats. The E(max) of NA in SHR was 1.82 times of that of WKY. The concentration-contractile curve induced by NA in great omental arteries of hypertensives significantly shifted toward left and the pD2 value of NA was larger than that of normotensives. After organ culture, the concentration-contractile curves of SD rat mesenteric artery induced by NA shifted toward left with significantly increased E(max). The relative amounts of mRNA for alpha1-adrenoreceptor was increased, but mRNA level for alpha2-adrenoreceptor did not change.


CONCLUSIONS
The sensitivity of alpha1-adrenoreceptor of artery smooth muscle in hypertensive man and rat is enhanced, suggesting alpha1-adrenoreceptor is upregulated.
Cao
Yong-Xiao
YX
Department of Pharmacology, School of Medicine, Xi'an Jiaotong University, Xi'an 710061, China. yxy@xjtu.edu.cn
Li
Jie
J
Liu
Hao
H
Luo
Guo-Gang
GG
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000818:Animals; D004305:Dose-Response Relationship, Drug; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D066298:In Vitro Techniques; D008638:Mesenteric Arteries / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology*; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology*; D009638:Norepinephrine / Q000494:pharmacology; D009852:Omentum / Q000098:blood supply; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D017207:Rats, Sprague-Dawley; D011942:Receptors, Adrenergic, alpha / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013045:Species Specificity; D014661:Vasoconstriction / Q000187:drug effects
D000316:Adrenergic alpha-Agonists; D012333:RNA, Messenger; D011942:Receptors, Adrenergic, alpha; D009638:Norepinephrine