Involvement of transient receptor potential melastatin type 7 channels on Poncirus fructus-induced depolarizations of pacemaking activity in interstitial cells of Cajal from murine small intestine.
Involvement of transient receptor potential melastatin type 7 channels on Poncirus fructus-induced depolarizations of pacemaking activity in interstitial cells of Cajal from murine small intestine.
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DOI：
10.1016/j.imr.2013.04.004
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发表时间：
2013-06
影响因子：
3.4
通讯作者：
Kim HW
中科院分区：
文献类型：
--
作者：
Kim BJ;Lee GS;Kim HW
枳壳（Poncirus trifoliata（L.）RAF.（芸香科; PT）在东亚被广泛用作传统药物，尤其用于治疗与胃肠道运动相关的胃肠道（GI）疾病。Cajal间质细胞（Interstitial cells of Cajal，ICCs）是胃肠道的起搏器，瞬时受体电位7型（transient receptor potential melastatin type 7，TRPM 7）通道和Ca 2+激活的Cl-通道是候选的起搏通道。在本研究中，使用全细胞膜片钳技术研究了PT干根的甲醇提取物对ICC起搏活性的影响。PT的甲醇提取物（PTE）被发现以浓度依赖的方式降低ICC簇的起搏电位的幅度和去极化静息膜电位。胞内GDP-β-S抑制PTE诱导的去极化，用U-73122（一种磷脂酶C抑制剂）或2-APB（一种1，4，5-三磷酸肌醇受体抑制剂）预处理可消除起搏电位的产生并抑制PTE诱导的效应。氟灭酸，尼氟灭酸，waixenicin A，或5-脂氧合酶抑制剂（NDGA或AA 861）的应用程序取消了这一产生的起搏电位和抑制PTE诱导的膜去极化。此外，PTE抑制TRPM 7通道，但不影响Ca 2+激活的Cl-通道（两个通道在调节与GI运动相关的起搏活性中起重要作用）。这些结果表明，PTE诱导的起搏活动的去极化发生在G-蛋白，磷脂酶C，和1，4，5-三磷酸肌醇依赖性的方式通过TRPM 7通道培养的ICC从小鼠小肠，这表明，ICC是PTE的目标和它们的相互作用影响肠运动。
Extracts of Poncirus trifoliata (L.) Raf. (Rutaceae; PT) are widely used as a traditional medicine in Eastern Asia, especially for the treatment of gastrointestinal (GI) disorders related to GI motility. Interstitial cells of Cajal (ICCs) are pacemakers in the GI tract, and transient receptor potential melastatin type 7 (TRPM7) channels and Ca2+ activated Cl– channels are candidate pacemaker channels. In the present study, the effects of a methanolic extract of the dried roots of PT on ICC pacemaking activity were examined using the whole-cell patch-clamp technique. The methanolic extract of PT (PTE) was found to decrease the amplitudes of pacemaker potentials in ICC clusters and to depolarize the resting membrane potentials in a concentration-dependent manner. Intracellular GDP-β-S suppressed PTE-induced depolarizations, and pretreatment with a U-73122 (a phospholipase C inhibitor) or with 2-APB (an 1,4,5-inositol triphosphate receptor inhibitor) abolished this generation of pacemaker potentials and suppressed PTE-induced effects. The applications of flufenamic acid, niflumic acid, waixenicin A, or 5-lipoxygenase inhibitors (NDGA or AA861) abolished this generation of pacemaker potentials and inhibited PTE-induced membrane depolarization. Furthermore, PTE inhibited TRPM7 channels but did not affect Ca2+-activated Cl– channels (both channels play important roles in the modulation of the pacemaking activity related to GI motility). These results suggest that the PTE-induced depolarization of pacemaking activity occurs in a G-protein-, phospholipase C-, and 1,4,5-inositol triphosphate-dependent manner via TRPM7 channels in cultured ICCs from murine small intestine, which indicates that ICCs are PTE targets and that their interactions affect intestinal motility.