@article{APS9268,
author = {Yu YAN and Yu-cai CHEN and Yi-huang LIN and Jing GUO and Zi-ran NIU and Li LI and Shou-bao WANG and Lian-hua FANG and Guan-hua DU},
title = {Brazilin isolated from the heartwood of Caesalpinia sappan L induces endothelium-dependent and -independent relaxation of rat aortic rings},
journal = {Acta Pharmacologica Sinica},
volume = {36},
number = {11},
year = {2017},
keywords = {},
abstract = {Aim: Brazilin is one of the major constituents of Caesalpinia sappan L with various biological activities. This study sought to investigate the vasorelaxant effect of brazilin on isolated rat thoracic aorta and explore the underlying mechanisms.
Methods: Endothelium-intact and -denuded aortic rings were prepared from rats. The tension of the preparations was recorded isometrically with a force displacement transducer connected to a polygraph. The phosphorylation levels of ERK1/2 and myosin light chain (MLC) were analyzed using Western blotting assay.
Results: Application of brazilin (10–100 μmol/L) dose-dependently relaxed the NE- or high K+-induced sustained contraction of endothelium-intact aortic rings (the EC50 was 83.51±5.6 and 79.79±4.57 μmol/L, respectively). The vasorelaxant effect of brazilin was significantly attenuated by endothelium removal or by pre-incubation with L-NAME, methylene blue or indomethacin. In addition, pre-incubation with brazilin dose-dependently attenuated the vasoconstriction induced by KCl, NE or Ang II. Pre-incubation with brazilin also markedly suppressed the high K+-induced extracellular Ca2+ influx and NE-induced intracellular Ca2+ release in endotheliumdenuded aortic rings. Pre-incubation with brazilin dose-dependently inhibited the NE-stimulated phosphorylation of ERK1/2 and MLC in both endothelium-intact and -denuded aortic rings.
Conclusion: Brazilin induces relaxation in rat aortic rings via both endothelium-dependent and -independent ways as well as inhibiting NE-stimulated phosphorylation of ERK1/2 and MLC. Brazilin also attenuates vasoconstriction via blocking voltage- and receptoroperated Ca2+ channels.},
issn = {1745-7254}, url = {http://www.chinaphar.com/article/view/9268}
}