MUCOSAL DEFENSE MECHANISMS IN SUBSTANCE ABUSE

药物滥用中的粘膜防御机制

• 批准号: 6174961
• 负责人: DAVID R BROWN
• 金额: $ 11.64万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-09-29 至 2001-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6174961
• 关键词: HIV envelope protein; Peyer's patches; confocal scanning microscopy; drug tolerance; gastrointestinal epithelium; immunocytochemistry; intestinal mucosa; morphine; mucosal immunity; opioid receptor; receptor binding; receptor expression; secretion; swine

DESCRIPTION: (Applicant's Abstract) The acquired immunodeficiency syndrome is associated with a high incidence of intestinal disease resulting from primary human immunodeficiency virus (HIV) infections and secondary opportunistic infections of the intestinal mucosa. The mucosa protects the immense surface area encompassed by the intestine from invasion by pathogenic microorganisms and controls proliferation of resident gut microflora. These protective mechanisms include: (1) active water and ion secretion which dilutes and purges luminal pathogens; (2) the integrity of the epithelium to macromolecular and microbial penetration; and (3) local immune reactions to luminal antigens mediated by gut-associated lymphoid tissue. Morphine and other opioids suppress immunity and decrease disease resistance in animals and humans. However, their ability to modify intestinal host defense mechanisms is not well defined. We hypothesize that opioids suppress mucosal defense through interactions with mucosal and submucosal opioid receptors (ORs). Thus, drugs of this class could reduce host resistance to intestinal infections and promote seeding of enteric microorganisms to extra-intestinal sites. Using the small intestine of normal and morphine-dependent pigs as an experimental model, we will test this hypothesis through the following specific aims: (1) localize ORs in the intestinal mucosa and submucosa through analyses of specific opioid binding sites and identification of OR mRNAs in epithelial cells and submucosal neurons, and localization of OR-like immunoreactivity on cholinergic and peptidergic submucosal neurons using novel anti-OR antisera; (2) characterize ORs which suppress mucosal secretion through electrophysiological measurements of transcellular ion fluxes across sheets of ileal mucosa-submucosa, elucidation of neurochemical circuits involved in opioid actions, and determination of opioid suppression of mucosal secretion induced by inflammatory mediators and HIV envelope proteins; (3) define opioid effects on epithelial barrier function through electrophysiological determinations of tissue conductance and quantitation of transepithelial microparticle penetration; and (4) assess the influence of morphine tolerance on opioid-induced changes in mucosal secretion, barrier function and the acquisition of local immune responses to specific antigens. This study will provide new and clinically important data on opioid actions in first-line mucosal defense against pathogens, such as HIV, that infect or emanate from the intestinal tract.

描述：（申请人摘要） 获得性免疫缺陷综合征的高发病率与 原发性人类免疫缺陷病毒引起的肠道疾病 (HIV) 肠道感染和继发性机会性感染 粘膜。 粘膜保护着由粘膜包围的巨大表面积 肠道免受病原微生物的侵袭和控制 常驻肠道微生物群的增殖。 这些保护机制 包括：（1）稀释和净化的活性水和离子分泌 腔内病原体； (2)上皮细胞大分子的完整性 微生物渗透； (3) 对管腔抗原的局部免疫反应 由肠道相关淋巴组织介导。 吗啡和其他阿片类药物 抑制动物和人类的免疫力并降低抗病能力。 然而，它们改变肠道宿主防御机制的能力并不 定义明确。 我们假设阿片类药物通过抑制粘膜防御 与粘膜和粘膜下阿片受体（OR）的相互作用。 因此， 此类药物可以降低宿主对肠道感染的抵抗力 并促进肠道微生物在肠外部位的播种。 使用正常猪和吗啡依赖猪的小肠作为 实验模型，我们将通过以下方式检验这个假设 具体目标：（1）将OR定位于肠粘膜和粘膜下层 通过分析特定阿片类药物结合位点并识别 OR 上皮细胞和粘膜下神经元中的 mRNA 及其定位 胆碱能和肽能粘膜下神经元的 OR 样免疫反应性 使用新型抗OR抗血清； (2) 表征抑制粘膜的 OR 通过跨细胞离子的电生理测量进行分泌 穿过回肠粘膜-粘膜下层的通量，神经化学物质的阐明 参与阿片类药物作用的电路以及阿片类药物抑制的测定 炎症介质和 HIV 包膜诱导的粘膜分泌 蛋白质； (3) 通过以下方式定义阿片类药物对上皮屏障功能的影响 组织电导和定量的电生理测定 跨上皮微粒渗透； (4)评估影响 吗啡耐受性对阿片类药物引起的粘膜分泌变化的影响， 屏障功能和获得特定的局部免疫反应 抗原。 这项研究将提供新的、具有临床意义的数据 阿片类药物在针对病原体（例如 HIV）的一线粘膜防御中的作用 感染或从肠道散发的。