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Evidence-Based Complementary and Alternative Medicine
Volume 2013, Article ID 404713, 12 pages
http://dx.doi.org/10.1155/2013/404713
Research Article

Ethanol Extract of Lepidium apetalum Seed Elicits Contractile Response and Attenuates Atrial Natriuretic Peptide Secretion in Beating Rabbit Atria

1School of Oriental Medicine & College of Oriental Medicine, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea
2Hanbang Body-Fluid Research Center, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea
3The College of Chinese Traditional Medicine, Yanbian University, Yanji, Jilin 133002, China

Received 15 March 2013; Accepted 9 September 2013

Academic Editor: Hao Xu

Copyright © 2013 Seung Ju Kim et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The seeds of Lepidium apetalum Willdenow (called “Tinglizi” in China and “Jungryukza” in Korea) have been used to discharge phlegm and improve dropsy in Oriental medicine. The present study investigated the effects of ethanol extract of the seeds of Lepidium apetalum (ELA) on atrial dynamics and atrial natriuretic peptide (ANP) secretion in beating rabbit atria. ELA increased atrial stroke volume, pulse pressure, and cAMP efflux, concomitantly attenuating ANP secretion in a dose-dependent manner. ELA-induced increases in atrial stroke volume, pulse pressure, and cAMP levels and decrease in ANP secretion were not inhibited by pretreatment with staurosporine, a nonspecific protein kinase inhibitor, or diltiazem and verapamil, the L-type Ca2+ channel blockers, respectively. Helveticoside, a well-known digitalis-like cardiac glycosidic constituent of ELA, also increased atrial dynamics, including stroke volume and pulse pressure, without changing cAMP efflux and ANP secretion, and the effects of helveticoside were not inhibited by pretreatment with staurosporine, diltiazem, and verapamil. These results suggest that the ELA-induced positive inotropic activity in beating rabbit atria might, at least partly, be due to the digitalis-like activity of helveticoside rather than an increase in cAMP efflux.