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1. chinaXiv:201605.01496 [pdf]

Relaxant Action of Plumula Nelumbinis Extract on Mouse Airway Smooth Muscle

Tan, Li; Chen, Weiwei; Wei, Ming-Yu; Shen, Jinhua; Yu, Meng-Fei; Liu, Qing-Hua; Tan, Li; Chen, Weiwei; Wei, Ming-Yu; Shen, Jinhua; Yu, Meng-Fei; Liu, Qing-Hua; Yang, Guangzhong; Guo, Donglin; Guo, Donglin; Qin, Gangjian; Ji, Guangju
Subjects: Biology >> Biophysics >> Integrative & Complementary Medicine

The traditional herb Plumula Nelumbinis is widely used in the world because it has many biological activities, such as anti-inflammation, antioxidant, antihypertension, and butyrylcholinesterase inhibition. However, the action of Plumula Nelumbinis on airway smooth muscle (ASM) relaxation has not been investigated. A chloroform extract of Plumula Nelumbinis (CEPN) was prepared, which completely inhibited precontraction induced by high K+ in a concentration-dependent manner in mouse tracheal rings, but it had no effect on resting tension. CEPN also blocked voltage-dependent L-type Ca2+ channel-(VDCC-) mediated currents. In addition, ACh-induced precontraction was also completely blocked by CEPN and partially inhibited by nifedipine or pyrazole 3. Besides, CEPN partially reduced ACh-activated nonselective cation channel (NSCC) currents. Taken together, our data demonstrate that CEPN blocked VDCC and NSCC to inhibit Ca2+ influx, resulting in relaxation of precontracted ASM. This finding indicates that CEPN would be a candidate of new potent bronchodilators.

submitted time 2016-05-12 Hits2082Downloads1309 Comment 0

2. chinaXiv:201605.01486 [pdf]

Involvement of Large-Conductance Ca2+-Activated K+ Channels in Chloroquine-Induced Force Alterations in Pre-Contracted Airway Smooth Muscle

Wei, Ming-Yu; Xue, Lu; Tan, Li; Sai, Wen-Bo; Liu, Xiao-Cao; Jiang, Qiu-Ju; Shen, Jinhua; Peng, Yong-Bo; Zhao, Ping; Yu, Meng-Fei; Chen, Weiwei; Ma, Li-Qun; Liu, Qing-Hua; Wei, Ming-Yu; Xue, Lu; Tan, Li; Sai, Wen-Bo; Liu, Xiao-Cao; Jiang, Qiu-Ju; Shen, Jinhua
Subjects: Biology >> Biophysics

The participation of large-conductance Ca2+ activated K+ channels (BKs) in chloroquine (chloro)-induced relaxation of precontracted airway smooth muscle (ASM) is currently undefined. In this study we found that iberiotoxin (IbTx, a selective inhibitor of BKs) and chloro both completely blocked spontaneous transient outward currents (STOCs) in single mouse tracheal smooth muscle cells, which suggests that chloro might block BKs. We further found that chloro inhibited Ca2+ sparks and caffeine-induced global Ca2+ increases. Moreover, chloro can directly block single BK currents completely from the intracellular side and partially from the extracellular side. All these data indicate that the chloro-induced inhibition of STOCs is due to the blockade of chloro on both BKs and ryanodine receptors (RyRs). We also found that low concentrations of chloro resulted in additional contractions in tracheal rings that were precontracted by acetylcholine (ACH). Increases in chloro concentration reversed the contractile actions to relaxations. In the presence of IbTx or paxilline (pax), BK blockers, chloro-induced contractions were inhibited, although the high concentrations of chloro-induced relaxations were not affected. Taken together, our results indicate that chloro blocks BKs and RyRs, resulting in abolishment of STOCs and occurrence of contraction, the latter will counteract the relaxations induced by high concentrations of chloro.

submitted time 2016-05-12 Hits1646Downloads962 Comment 0

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