Calcimimetic R568 inhibits tetrodotoxin-sensitive colonic electrolyte secretion and reduces c-fos expression in myenteric neurons.
Calcimimetic R568 inhibits tetrodotoxin-sensitive colonic electrolyte secretion and reduces c-fos expression in myenteric neurons.
复制标题
Calcimimetic R568 抑制河豚毒素敏感的结肠电解质分泌并减少肌间神经元中的 c-fos 表达。
DOI：
10.1016/j.lfs.2017.12.019
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发表时间：
2018
期刊：
影响因子：
6.1
通讯作者：
Cheng,SamXianjun
中科院分区：
文献类型：
--
作者：
Sun,Xiangrong;Tang,Lieqi;Winesett,Steven;Chang,Wenhan;Cheng,SamXianjun
钙敏感受体（CaSR）在肠神经系统（ENS）粘膜下神经丛和肌肠丛神经元上均有表达，CaSR激动剂R568可抑制肠内Cl−的分泌。本研究的目的是定位R568在ENS中的主要作用部位，并探讨CaSR如何通过ENS调节分泌。材料和方法采用大鼠近端和远端结肠两种制剂。全层制备包括粘膜下肌丛和肌丛，而“剥离”制备只包括肌层肌丛。两种制剂均安装在Ussing腔上，通过测量短路电流（Isc）的变化来比较Cl -分泌反应。两种组织特异性CaSR敲除（即神经元特异性）。通过免疫细胞化学方法比较R568对肌肠神经元c-fos蛋白表达的影响。在全层结肠中，河豚毒素（TTX）抑制了近端和远端结肠的disc。R568产生了几乎相同的抑制作用。然而，在剥离制剂中，虽然TTX对isl的作用仍然明显，但R568的作用几乎完全消除。与此相一致的是，R568仅在神经元中含有CaSR的野生型小鼠和突变型小鼠（即villinCre/Casrflox/floxmice）的肌肠神经元中降低了c-fos蛋白的表达，而在神经元细胞CaSR被消除的巢型小鼠/Casrflox/floxmice的肌肠神经元中没有降低c-fos蛋白的表达。这些结果表明R568主要通过casr介导的对肌肠丛神经元活性的抑制来发挥其抗分泌作用。
AimsCalcium-sensing receptor (CaSR) is expressed on neurons of both submucosal and myenteric plexuses of the enteric nervous system (ENS) and the CaSR agonist R568 inhibited Cl−secretion in intestine. The purpose of this study was to localize the primary site of action of R568 in the ENS and to explore how CaSR regulates secretion through the ENS.Materials and methodsTwo preparations of rat proximal and distal colon were used. The full-thickness preparation contained both the submucosal and myenteric plexuses, whereas for the “stripped” preparation the myenteric plexus with the muscle layers was removed. Both preparations were mounted onto Ussing chambers and Cl−secretory responses were compared by measuring changes in short circuit current (Isc). Two tissue-specific CaSR knockouts (i.e., neuron-specificvs.enterocyte-specific) were generated to compare the effect of R568 on expression of c-fos protein in myenteric neurons by immunocytochemistry.Key findingsIn full-thickness colons, tetrodotoxin (TTX) inhibitedIsc, both in proximal and distal colons. A nearly identical inhibition was produced by R568. However, in stripped preparations, while the effect of TTX onIsclargely remained, the effect of R568 was nearly completely eliminated. In keeping with this, R568 reduced c-fos protein expression only in myenteric neurons of wild type mice and mutant mice that contained CaSR in neurons (i.e., villinCre/Casrflox/floxmice), but not in myenteric neurons of nestinCre/Casrflox/floxmice in which neuronal cell CaSR was eliminated.SignificanceThese results indicate that R568 exerts its anti-secretory effects predominantly via CaSR-mediated inhibition of neuronal activity in the myenteric plexus.