PSYCHOPHYSIOLOGY OF IRRITABLE BOWEL SYNDROME

这是一个申请竞争性更新的补助金，以研究 肠易激综合征，一种以腹痛为特征的疾病， 排便习惯改变，影响高达17%的人口， 占胃肠病学家转诊的20-50%。 疼痛改变 感知似乎是其主要症状。 易激 肠更可能报告腹部结肠压痛 触诊，他们报告疼痛和（无痛）紧急排便， 球囊扩张阈值较低。 形成的物理机制 改变的疼痛感知是未知的，但对内脏的基础研究 疼痛暗示了四种可能性：感觉的数量或类型的改变 肌肉或肠系膜中的神经末梢，肌肉张力或运动性改变 与继发性超敏反应，粘膜受体的敏感性， 炎症过程和CNS介导的心理影响， 痛阈 实验I将通过以下方式来研究这些假设： 比较20名健康对照组和30名肠易激综合征患者。 的 三种感觉的阈值与扩张的 乙状结肠-最小可检测到的膨胀，排便欲望和疼痛 - 将通过心理物理跟踪程序进行测试，以控制 知觉偏差 利多卡因将用于确定是否 这三种感觉的感受器位于粘膜或肌肉中 或肠系膜周围。 收缩活动将测量为 通过灌注导管近端和远端检测到的压力变化 到气球。 肌肉张力将通过恒压技术测量 其中维持恒定低压所需的空气体积 (10 mmHg）的压力下监测10分钟。 在 实验二，疼痛阈值将在18整个结肠测试 肠易激综合征患者，以确定敏感性增加的区域 （由其他研究人员报告）。 在这些区域，利多卡因将 以确定疼痛感受器是否位于 粘膜或更深的结构，活检将通过 内窥镜检查，以确定疼痛是否与合成增加有关， 细胞因子或神经肽。 在实验III中， 疼痛感知的生理偏差将由一个 信号检测范例，其中20名患者和20名对照被要求 来区分两种不同程度的结肠扩张， 接近疼痛的阈值。 组将与 感知灵敏度和反应偏差。

This is an application for competitive renewal of a grant to study the irritable bowel syndrome, a disorder characterized by abdominal pain and altered bowel habits, which affects up to 17% of the population and accounts for 20-50% of referrals to gastroenterologists. Altered pain perception appears to be its cardinal symptom. Patients with irritable bowel are more likely to report tenderness over the colon on abdominal palpation, and they report pain and (non-painful) urgency to defecate at lower thresholds of balloon distension. The mechanism responsible for altered pain perception are not known, but basic research on visceral pain suggests four possibilities: altered numbers or types of sensory nerve endings in muscle or mesentery, altered muscle tone or motility with secondary hypersensitivity, sensitization of mucosal receptors by inflammatory processes, and CNS-mediated psychological influences on pain threshold. Experiment I will investigate these hypotheses by comparing 20 health controls to 30 irritable bowel patients. The thresholds for three sensations associated with distension of the sigmoid colon-smallest detectable distension, urge to defecate, and pain - will be tested by a psychophysical tracking procedure to control for perceptual bias. Lidocaine will be used to determine whether the receptors for these three sensations lie in the mucosa or in the muscle or surrounding mesentery. Contractile activity will be measured as pressure changes detected through perfused catheters proximal and distal to the balloon. Muscle tone will be measured by the barostat technique in which the volume of air required to maintain a constant low pressure (10 mm Hg) in a distending balloon is monitored for 10 minutes. In Experiment II, pain thresholds will be tested throughout the colon in 18 patients with irritable bowel to identify zones of increased sensitivity (reported by other investigators). In these areas, lidocaine will be infused to determine whether the pain receptors are located in the mucosa or in deeper structures, and biopsies will be obtained by endoscope to determine whether pain is related to increased synthesis of cytokines or neuropeptides. In Experiment III, the effects of physiological bias on the perception of pain will be investigated by a signal detection paradigm in which 20 patients and 20 controls are asked to discriminate between two different amounts of colonic distension at approximately the threshold for pain. Groups will be compared with respect to both perceptual sensitivity and response bias.