School of Chinese Medicine
Magnolol inhibits colonic motility through down-regulation of voltage-sensitive L-type Ca2+ channels of colonic smooth muscle cells in rats
This study aimed to investigate the effect of magnolol (5,5′-diallyl- 2,2′-biphenyldiol) on contraction in distal colonic segments of rats and the underlying mechanisms. Colonic segments were mounted in organ baths for isometric force measurement. Whole-cell voltage-sensitive L-type Ca2+ currents were recorded on isolated single colonic smooth muscle cells using patch-clamp technique. The spontaneous contractions and acetylcholine (ACh)- and Bay K 8644-induced contractions were inhibited by magnolol (3-100 μM). In the presence of Bay K8644 (100 nM), magnolol (10-100 μM) inhibited the contraction induced by 10 μM ACh. By contrast, tetrodotoxin (100 nM) and Nώ-nitro-l-arginine methyl ester (l-NAME 100 μM) did not change the inhibitory effect of magnolol (10 μM). In addition, magnolol (3-100 μM) inhibited the L-type Ca2+ currents. The present results suggest that magnolol inhibits colonic smooth muscle contraction through downregulating L-type Ca2+ channel activity. © 2013 Elsevier GmbH.
Colonic motility, L-type Ca2+ channels, Magnolia officinalis, Magnolol, Smooth muscle cells
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Zhang, Man, Kai-Hong Zang, Jia-Lie Luo, Fung-Ping Leung, Yu Huang, Cheng-Yuan Lin, Zhi-Jun Yang, Ai-Ping Lu, Xu-Dong Tang, Hong-Xi Xu, Joseph Jao-Yiu Sung, and Zhao-Xiang Bian. "Magnolol inhibits colonic motility through down-regulation of voltage-sensitive L-type Ca2+ channels of colonic smooth muscle cells in rats." Phytomedicine 20.4 (2013): 1272-1279.