Cellular Physiology of Sensory Ion Channels

描述(由申请人提供)：这项提案的长期目标是了解我们的神经系统如何检测和处理环境中的信息，并将这些环境刺激转换为电化学事件。我们的方法是利用天然植物产品的药理作用，特别是那些引起刺激或不适的产品，以揭示涉及体感神经系统神经元检测有害刺激的新的信号机制。事实上，这种方法在发现和分析细胞表面受体和酶方面已经被证明是非常有成效的，这些受体和酶对于检测和调节产生疼痛的刺激非常重要，例如使用从植物中提取的产品，如阿司匹林、吗啡、辣椒素和薄荷醇，分别发现环生酶、阿片受体和温度敏感的Trp通道。这一应用的一个主要焦点是确定来自芥末植物(如芥末)的刺激性异硫氰酸酯化合物如何通过激活初级感觉神经元上的兴奋通道TRPA1来兴奋感觉神经元。目前尚不清楚这些药物如何作为TRPA1通道的选择性激动剂。我们将使用遗传、化学和电生理方法的组合来解决这个问题，对这些方法的回答将为促进TRPA1的激活和/或调节的内源性机制提供重要的见解。除了充当“山葵受体”外，TRPA1可能还参与了炎症产物，如缓激肽、组胺或5-羟色胺等刺激感觉神经元的机制。因此，我们的另一个目标是使用培养的来自正常和TRPA1缺陷小鼠的感觉神经元来确定TRPA1是否有助于这些兴奋行为，如果是的话，这个过程背后的细胞信号机制是什么。最后，我们还建议检测其他天然产物对培养的感觉神经元的影响，目的是开发新的药理探针，用来发现或表征有助于检测或调节感觉刺激的重要细胞信号机制。这些研究可能会刺激新型止痛药的设计和开发，用于治疗周围疼痛综合征，如关节炎或病毒性和糖尿病神经病变。

DESCRIPTION (provided by applicant): The long-term objective of this proposal is to understand how our nervous system detects and processes information in our environment and transduces such environmental stimuli into electrochemical events. Our approach is to exploit the pharmacological power of natural plant products, specifically those that elicit irritation or discomfort, to uncover novel signaling mechanisms involved in the detection of noxious stimuli by neurons of the somatosensory nervous system. Indeed, this approach has proven to be extremely fruitful in the discovery and analysis of cell surface receptors and enzymes that are important for the detection and modulation of pain-producing stimuli, as illustrated by the use of plant-derived products such as aspirin, morphine, capsaicin, and menthol to discover cycloogenases, opiate receptors, and thermosensitive TRP channels, respectively. A major focus of this application is to determine how pungent isothiocyanate compounds from mustard plants (such as wasabi) excite sensory neurons by activating TRPA1, an excitatory channel on primary sensory neurons. It is currently unknown how these agents serve as selective agonists for the TRPA1 channel. We will use a combination of genetic, chemical, and electrophysiological methods to address this question, answers to which should provide significant insight into endogenous mechanisms that promote the activation and/or modulation of TRPA1. In addition to serving as a "wasabi receptor", TRPA1 may contribute to the mechanism whereby inflammatory products, such as bradykinin, histamine, or serotonin excite sensory neurons. Thus, another of our aims is to use cultured sensory neurons from normal and TRPA1-deficient mice to determine whether TRPA1 contributes to these excitatory actions and, if so, what cellular signaling mechanisms underlie this process. Finally, we are also proposing to examine effects of other natural products on cultured sensory neurons with the aim of developing novel pharmacological probes with which to discover or characterize important cellular signaling mechanisms that contribute to the detection or modulation of sensory stimuli. These studies may stimulate the design and development of novel analgesic agents for treating peripheral pain syndromes, such as arthritis or viral and diabetic neuropathies.