Hattay Priya, Prusator Dawn K, Johnson Anthony C, Greenwood-Van Meerveld Beverley
Oklahoma Center for Neurosciences and Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.
Veterans Affairs Medical Center, Oklahoma City, OK, United States.
Front Neurosci. 2018 Aug 7;12:543. doi: 10.3389/fnins.2018.00543. eCollection 2018.
Irritable bowel syndrome (IBS) is characterized by visceral pain and abnormal bowel habits that are worsened during stress. Evidence also suggests altered intestinal barrier function in IBS. Previously, we demonstrated that stereotaxic application of the stress hormone corticosterone (CORT) onto the central nucleus of the amygdala (CeA) induces colonic hyperalgesia and anxiety-like behavior in a rat model, however the effect on intestinal permeability and mucosal function remain to be evaluated. Male Fischer 344 rats underwent bilateral stereotaxic implantation of CORT or inert cholesterol (CHOL)-containing micropellets (30 μg) onto the dorsal margin of the CeA. Seven days later, colonic tissue was isolated to assess tissue permeability in modified Ussing chambers via transepithelial electrical resistance (TEER) and macromolecular flux of horseradish peroxidase (HRP). Secretory responses to electrical field stimulation (EFS) of submucosal enteric nerves as well as activation with forskolin were used to assess movements of ions across the isolated colonic tissues. In a separate cohort, colonic histology, and mast cell infiltration was assessed. Compared to CHOL-implanted controls, we determined that exposing the CeA to elevated levels of CORT significantly increased macromolecular flux across the colonic epithelial layer without changing TEER. Nerve-mediated but not cAMP-mediated active transport was inhibited in response to elevated amygdala CORT. There were no histological changes or increases in mast cell infiltration within colonic tissue from CORT treated animals. These observations support a novel role for the CeA as a modulator of nerve-mediated colonic epithelial function.
肠易激综合征(IBS)的特征是内脏疼痛和异常排便习惯,在应激期间会加重。有证据还表明IBS患者的肠道屏障功能发生了改变。此前,我们证明,在大鼠模型中,将应激激素皮质酮(CORT)立体定向注射到杏仁核中央核(CeA)上会诱发结肠痛觉过敏和焦虑样行为,然而其对肠道通透性和黏膜功能的影响仍有待评估。雄性Fischer 344大鼠接受双侧立体定向手术,将含CORT或惰性胆固醇(CHOL)的微丸(30μg)植入CeA的背侧边缘。7天后,分离结肠组织,通过跨上皮电阻(TEER)和辣根过氧化物酶(HRP)的大分子通量在改良的Ussing室中评估组织通透性。利用对黏膜下肠神经电场刺激(EFS)的分泌反应以及用福司可林激活来评估离子在分离的结肠组织中的转运。在另一组实验中,评估结肠组织学和肥大细胞浸润情况。与植入CHOL的对照组相比,我们发现将CeA暴露于高水平的CORT会显著增加结肠上皮层的大分子通量,而不改变TEER。对杏仁核CORT水平升高的反应是,神经介导而非cAMP介导的主动转运受到抑制。CORT处理动物的结肠组织内没有组织学变化或肥大细胞浸润增加。这些观察结果支持CeA作为神经介导的结肠上皮功能调节因子的新作用。