PSYCHOPHYSIOLOGY OF IRRITABLE BOWEL SYNDROME

这是一份申请竞争性续期助学金的申请 肠易激综合征，一种以腹痛和腹痛为特征的疾病 改变排便习惯，影响多达17%的人口和 占转诊给胃肠病医生的20%-50%。改变的疼痛 感知似乎是它的主要症状。易激惹的患者 在腹部，肠道更容易报告为结肠压痛 触诊，他们报告疼痛和(非疼痛)排便急迫 降低气囊扩张的门槛。负责的机制 改变的痛觉是未知的，但对内脏的基础研究 疼痛提示四种可能性：数量或感觉类型的改变 肌肉或肠系膜的神经末梢，肌肉张力或运动性改变 在继发性超敏反应中，粘膜受体的敏化 炎症过程，以及中枢神经系统介导的心理影响 疼痛阈值。实验I将通过以下方式研究这些假设 将20名健康对照组与30名肠易激患者进行比较。这个 与关节扩张相关的三种感觉的阈值 乙状结肠-可检测到的最小的肿胀、排便冲动和疼痛 -将通过心理物理跟踪程序进行测试，以控制 感觉上的偏见。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 或周围的肠系膜。收缩活动将被测量为 经灌流导管近端和远端检测到的压力变化 送到气球上。肌肉张力将通过恒压技术进行测量 其中维持恒定低压所需的空气量 (10毫米汞)在膨胀的气球中监测10分钟。在……里面 实验二，将在18年测试整个结肠的痛阈值 肠易激患者识别敏感区 (其他调查人员报道)。在这些地区，利多卡因将被 注入以确定疼痛感受器是否位于 粘膜或更深层的结构，活检将通过 内窥镜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， 将通过一项关于疼痛感知的生理偏差进行调查 信号检测范式，询问20名患者和20名对照 区分两种不同程度的结肠扩张 大约是疼痛的门槛。组将与 既要尊重感知敏感度，又要注意反应偏差。

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.