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- Title
17ß-Estradiol inhibits calcium-dependent, but not calcium-independent, contraction in isolated rat aorta.
- Authors
Hae-Ahm Lee; YuJin Seong; Won-Jung Lee; InKyeom Kim
- Abstract
It is now well known that 17ß-estradiol has an endothelium-independent, non-genomic vasorelaxant effect. We hypothesized that 17ß-estradiol has its non-genomic effect on calcium-independent contraction in de-endothelialized rat aortic rings. Rat aortic ring preparations were mounted in organ baths and exposed to contractile agents. 17ß-Estradiol (8, 20 or 50 µM), but not 17a-estradiol, concentration-dependently decreased the tension induced by 1.0 µM phenylephrine (PE) in the presence, but not in the absence, of calcium in the solution. Pretreatment with 17ß-estradiol concentration-dependently inhibited vascular contractions induced by cumulative addition of PE or calcium and almost completely abolished those induced by cumulative addition of Bay K8644, a calcium channel opener. Furthermore, 17ß-estradiol also concentration-dependently decreased the tension induced by 0.3 µM phorbol 12,13-dibutyrate (PDBu), a protein kinase C activator, in the presence of calcium in the solution, but not in the absence of calcium in the solution. Pretreatment with 17ß-estradiol had little effect on vascular contractions induced by PDBu or PE or on PE-induced mitogen-activated protein kinase (MAPK) activation in calcium-free Krebs solution. These results suggest that 17ß-estradiol inhibits calcium-dependent, but not calcium-independent, vascular contraction.
- Subjects
ESTRADIOL; AORTA; ENDOTHELIUM; CALCIUM in the body; STEROLS; PROTEIN kinases
- Publication
Naunyn-Schmiedeberg's Archives of Pharmacology, 2005, Vol 371, Issue 2, p152
- ISSN
0028-1298
- Publication type
Article
- DOI
10.1007/s00210-004-1017-3