Stress-Induced Activition of Colonic Motor Function

促肾上腺皮质激素释放因子(CRF)和尿皮质激素(UCN)1与两个Gs偶联的cRFI和CRF2相互作用 感受器。近年来，新的CRF相关多肽UCN-2和UCN-3被发现为选择性CRF-2 激动剂。激活CRF！大脑中的信号通路复制了整个内分泌，自主神经， 对压力的本能反应和行为反应。在上一次授权期内，我们确定，此外 对于大脑来说，肠道是外周注射CRF配体的反应目标，这提供了第一个证据 CRF2介导的胃抑制和CRFR介导的结肠刺激运动功能。此外，我们 外周注射促肾上腺皮质激素释放激素拮抗剂可减轻束缚和刺激引起的肠运动改变。 低剂量的内毒素。该提案的总体目标是建立肠道CRF受体 信号系统作为胃抑制和结肠双重刺激的局部效应肢体 应激对大鼠肠道功能的影响。目标1将检验这样的假设，即存在不同的轮廓 CRF配体(CRF、UCN 1、UCN 2和UCN 3)和受体(CRF！和CRF2)基因在胃中的表达 和受这些应激源调节的结肠，使用RT-PCR在激光捕获显微解剖层中 胃和结肠组织，免疫化学定位，自主神经和糖皮质激素的阻断。目标2 将确定外周CRF刺激结肠功能的机制涉及直接 激活CRF！结肠肠道胆碱能细胞和肠嗜铬细胞上的受体，使用Fos， 双重标记，监测递质释放，以及新型外周作用的cRFI激动剂和 体内和体外的拮抗剂。目的3将显示外周UCN-2介导的抑制的机制 胃排空包括超声显微测量描绘的胃和括约肌运动的改变和 胃壁内兴奋性胆碱能神经传递和抑制性神经传递的调制 使用RNAi特异性沉默CRF2受体。总体而言，这些研究将提供准确的 胃和结肠促肾上腺皮质激素释放因子配体和同源受体的表达及其在这些部位的调节 应激，以及它们在胃和结肠的双重局部作用的机制。此外，它还将 锚定肠道CRF信号系统作为应激相关肠道运动中生理效应肢体的一部分 改装。这可能为功能性肠病的管理提供新的策略。

Corticotropin-releasing factor (CRF) and urocortin (Ucn) 1 interact with two Gs coupled CRFi and CRF2 receptors. Recently, new CRF-related peptides, Ucn 2 and Ucn 3, were discovered as selective CRF2 agonists. Activation of CRF! signaling pathways in the brain reproduces the overall endocrine, autonomic, visceral and behavioral responses to stress. During the last granting period, we established that, in addition to the brain, the gut is a target responsive to peripheral injection of CRF ligands providing the first evidence of CRF2-mediated gastric inhibition and CRFrmediated colonic stimulation of motor function. In addition, we showed that peripheral injections of CRF antagonists alleviate gut motor alterations induced by restraint and a low dose of endotoxin. The overall objective of the proposal is to establish that the gut CRF receptor signaling system serves as a local effector limb for the dual gastric inhibitory and colonic stimulatory influence of stress on gut function in rats. Aim 1 will test the hypothesis that there is a differential profile of CRF ligand (CRF, Ucn 1, Ucn 2 and Ucn 3) and receptor (CRF! and CRF2) gene expression in the stomach and colon that is regulated by these stressors using RT-PCR in laser capture microdissected layers of gastric and colonic tissues, immunochemical localization, and autonomic and glucocorticoid blockade. Aim 2 will establish that the mechanisms through which peripheral CRF stimulates colonic function involve direct activation of CRF! receptors on colonic enteric cholinergic and enterochromaffin (EC) cells, usingFos, double labeling, monitoring of transmitter release, and novel peripherally acting CRFi agonist and antagonists in vivo and in vitro. Aim 3 will show that mechanisms of peripheral Ucn 2-mediated inhibition of gastric emptying involve alterations of gastric and sphincter motility delineated by ultrasonomicrometry and modulation of excitatory cholinergic and inhibitory neurotransmission at sites within the gastric wall identified using specific silencing of CRF2 receptor with RNAi. As a whole, these studies will provide accurate expression of gastric and colonic CRF ligands and cognate receptors, their regulation at these sites under stress, and mechanisms underlying their dual local actions on the stomach and colon. In addition, it will anchor the gut CRF signaling system as part of the physiological effector limb in stress-related gut motor alterations. This could underpin novel strategies for management of functional bowel disorders.