Psychophysical Studies of Itch

瘙痒的心理物理学研究

• 批准号: 7658801
• 负责人: Matthias Ringkamp
• 金额: $ 25.1万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7658801
• 关键词: Affect; Afferent Neurons; Afferent Pathways; Area; Burn injury; Capsaicin; Chemicals; Chronic; Clinical; Code; Condition; Cutaneous; Dermatitis; Development; Dose; Eczema; Effectiveness; Esthesia; Evaluation; Heating; Histamine; Hyperalgesia; Hypesthesia; Incidence; Insect Bites; Kindling (Neurology); Label; Measurement; Mechanics; Mediating; Medical; Modality; Neurons; Nociception; Numbers; Outcome Study; Pain; Pharmaceutical Preparations; Primary Hyperalgesias; Property; Pruritus; Psychophysics; Psychophysiology; Rate; Secondary Hyperalgesias; Sensory; Site; Skin; Stimulus; Sting Injury; Stroke; Symptoms; System; Systemic disease; Testing; Time; Topical application; allodynia; conditioning; design; drug development; heat stimulus; neuromechanism; novel; research study; response; skin disorder

Itching (pruritus) is a major clinical problem and one of the most disturbing symptoms of cutaneous and many systemic diseases. In normal skin, itch can be evoked by a variety of transient stimuli with no changes in cutaneous sensitivity. In contrast, under pathological conditions brought on, for example, by dermatitis, insect bites or experimentally by the application of a pruritic chemical such as histamine, a heightened pruritic state ("itchy skin") develops within and surrounding the affected skin. In itchy skin, normally pruritic stimuli elicit an enhanced itch (hyperknesis) and innocuous stimuli can evoke or enhance an ongoing itch or evoke an enhanced pain (alloknesis and hyperalgesia, respectively). There are few studies of the psychophysics of itch or of the somatic afferent pathways mediating itch. Similarly, there have been few psychophysical studies of the inhibition of itch or studies of the neural mechanisms mediating the inhibition. We propose psychophysical studies of itch, and its modulation by painful and other non-pruritic cutaneous stimuli, in normal skin and in chemically induced itchy skin. For both normal and itchy skin we will use a single adjective-labeled scale to compare the magnitude and time course of itch and pain sensations evoked by mechanical, heat and chemical stimuli. Differences in the magnitude and time course of itch and pain sensations evoked by each stimulus can be used in projects 2 and 3 to distinguish itch- from pain-coding sensory neurons. We will test the effects of non-pruritc conditioning stimuli (CS) in modulating itch in normal skin, itch in itchy skin and the development and persistence of itchy skin. We will test the hypothesis that there are two pruriceptive systems, one mediating itch, the other itchy skin and that each of these is under the inhibitory control of two different nociceptive systems - one operating within the area exposed to the CS and mediating pain or primary hyperalgesia, the other operating over a wider area and mediating secondary hyperalgesia and/or allodynia. The outcome of these studies will not only increase our understanding of itch and itchy skin. They will also provide novel information on endogenous mechanisms that inhibit itch and that may be appropriate targets for the development of drugs to control itching.

瘙痒（瘙痒症）是一个主要的临床问题，也是皮肤和许多疾病的最令人不安的症状之一。 系统性疾病。在正常皮肤中，瘙痒可由各种瞬时刺激诱发，而在皮肤中没有变化。 皮肤敏感性相比之下，在例如由皮炎引起的病理条件下，昆虫 叮咬或实验性地应用过敏性化学物质，如组胺，一种增强的过敏状态 皮肤瘙痒（“皮肤瘙痒”）在受影响的皮肤内和周围发展。在瘙痒的皮肤中，通常的瘙痒刺激会引起 增强的瘙痒（感觉过敏）和无害的刺激可以引起或增强正在进行的瘙痒或引起 增强的疼痛（分别为感觉异常和痛觉过敏）。关于瘙痒的心理物理学研究很少 或介导瘙痒的躯体传入途径。同样，很少有心理物理学研究 瘙痒的抑制或调节抑制的神经机制的研究。我们提出 瘙痒的心理物理学研究，以及疼痛和其他非过敏性皮肤刺激对瘙痒的调节， 正常皮肤和化学诱导的瘙痒皮肤。对于正常和发痒的皮肤，我们将使用一个单一的 形容词标记的量表，以比较 机械、热和化学刺激。瘙痒和疼痛的幅度和时间过程的差异 每个刺激引起的感觉可用于项目2和3中，以区分瘙痒编码和疼痛编码 感觉神经元我们将测试非条件反射刺激（CS）在调节瘙痒中的作用， 正常皮肤、瘙痒皮肤中的瘙痒以及瘙痒皮肤的发展和持续。我们将检验这个假设 有两个痛觉系统，一个调节瘙痒，另一个调节皮肤瘙痒，每一个都在 两个不同的伤害感受系统的抑制控制-一个在暴露于CS的区域内操作 和介导疼痛或原发性痛觉过敏，另一个在更广泛的区域操作并介导继发性痛觉过敏。 痛觉过敏和/或异常性疼痛。这些研究的结果不仅会增加我们对瘙痒的理解， 皮肤发痒它们还将提供关于抑制瘙痒的内源性机制的新信息， 可能是开发控制瘙痒药物的合适目标。