Effects of beta-adrenoceptor stimulation on endothelial nitric-oxide synthase phosphorylation of human umbilical vein endothelial cells.
OBJECTIVE
To investigate the effects of isoprenaline on the phosphorylation level of endothelial nitric oxide synthase (eNOS) of human umbilical vein endothelial cells (HUVEC) and to elucidate the regulation mechanisms of beta-adrenoceptor (beta-AR) on eNOS activity.


METHODS
HUVEC were exposed to isoprenaline (1 micromol/L) for 30 min, in the absence or presence of selective beta1- or beta2 -adrenoceptor antagonists. eNOS was then isolated by immunoprecipitation using a specific eNOS antibody. eNOS activity was determined by the conversion of L-[3H]arginine to L-[3H]citrulline. The levels of eNOS expression and eNOS phosphorylation were measured by Western blotting.


RESULTS
Treatment of HUVEC with isoprenaline (1 micromol/L) for 30 min caused no measureable change in eNOS expression. However, eNOS activity and serine phosphorylation level were significantly increased (P<0.01). This effect could be abolished by a selective beta2-adrenoceptor antagonist ICI 118551.


CONCLUSIONS
Isoprenaline increases eNOS activity of HUVEC, this is mediated by beta2-adrenoceptor and associated with an increase of eNOS serine phosphorylation level.
Yao
Kang
K
Department of Cardiology, Affiliated Zhong Da Hospital of Southeast University, Nanjing 210009, China.
Xu
Biao
B
Liu
Ya-Ping
YP
Ferro
Albert
A
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000201:enzymology*; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III; D010766:Phosphorylation; D011412:Propanolamines / Q000494:pharmacology; D014471:Umbilical Veins / Q000166:cytology / Q000201:enzymology
D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; C026777:ICI 118551; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; D007545:Isoproterenol