Brazilin isolated from the heartwood of Caesalpinia sappan L induces endothelium-dependent and -independent relaxation of rat aortic rings.
Acta Pharmacol Sin
; 36(11): 1318-26, 2015 Nov.
Article
in En
| MEDLINE
| ID: mdl-26564314
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 Ca(2+) influx and NE-induced intracellular Ca(2+) release in endothelium-denuded 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 receptor-operated Ca(2+) channels.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Aorta
/
Vasodilation
/
Vasodilator Agents
/
Benzopyrans
/
Endothelium, Vascular
Limits:
Animals
Country/Region as subject:
America do sul
/
Brasil
Language:
En
Journal:
Acta Pharmacol Sin
Journal subject:
FARMACOLOGIA
Year:
2015
Type:
Article
Affiliation country:
China