title: Vasorelaxation Effect of Estrone Derivate EA204 in Rabbit Aorta.
abstract: Estrogen and its derivatives exert vascular protective effects, but the underlying mechanisms remain to be studied fully. Objective. To investigate the vasorelaxation effect and related mechanisms of an estrone derivate EA204[3-(2-piperidin-1-yl)-ethoxy-estra-1, 3, 5 (10)-trien-17-one] on isolated arterial preparation from rabbit thoracic aorta. Methods. Aortic rings from rabbit thoracic aorta were prepared and held in small organ bath filled with Krebs solution; tension change was recorded by a multichannel physiological signal collection and handling system. Results. EA204 (10(-5) to 10(-3) M) induced a concentration-dependent relaxation of aortic rings with endothelium and without endothelium. In denuded arterial preparations, EA204 had a potent relaxing effect on isolated arterial preparations contracted with phenylephrine, norepinephrine, and high-K(+) solution or BaCl2. Mechanism study indicates that EA204 relaxes aortic rings by inhibiting Ca(2+) channels (both receptor-operating Ca(2+) channels and the voltage-dependent Ca(2+) channels were involved) to decrease extracellular Ca(2+) influx and intracellular Ca(2+) release. EA204 is different from verapamil, which is a noncompetitive inhibitor of Ca(2+) channels. In addition, K(+) channels opening may contribute to this vasorelaxation effect. Conclusion. EA204 had a potent endothelium-independent relaxing effect on isolated arterial preparation by inhibiting Ca(2+) channels and opening K(+) channels. The results suggest that EA204 is a potential compound for treatment of cardiovascular diseases in postmenopausal women.
authors.affiliation: School of Pharmacy, Ningxia Medical University, Yinchuan 750004, China; Ningxia Engineering and Technology Research Center for Modernization of Hui Medicine, Yinchuan 750004, China.
authors.forename: Juan
authors.identifier: 0000-0003-4245-4679
authors.initials: J
authors.lastname: Li
authors.affiliation: National Resource Center of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China; China National Center for Biotechnology Development, Beijing 100039, China.
authors.forename: Wei-Qi
authors.initials: WQ
authors.lastname: Li
authors.affiliation: School of Basic Medical Science, Ningxia Medical University, Yinchuan 750004, China; Research Center of Medical Science and Technology, Ningxia Medical University, Yinchuan 750004, China.
authors.forename: Yao
authors.identifier: 0000-0001-7459-2107
authors.initials: Y
authors.lastname: Yao