CHARACTERIZATION OF NOVEL NEUROACTIVE COMPOUNDS FROM CNIDARIA VENOMS

历史证明，毒液是强大的神经活性物质的丰富来源。最近发现的SNX-325，一种B类（n型）钙通道的选择性阻滞剂，为临床医生提供了一种治疗顽固性疼痛的新药物。目前可用的钙通道药物，包括二氢吡啶，其靶通道在功能和药理学上与外周l型通道不同，其治疗调节的探索受到目前缺乏特异性激动剂和拮抗剂的限制。针对这些通道的药物将是有用的，例如，在减少缺血期间由过量钙进入引起的神经元损伤方面。申请人实验室最近的研究结果表明，夏威夷水腔肠动物中最强大的毒液，Carybdea alata毒液，至少含有三种不同的活性。提出的合作研究的总体目标是增强申请人的能力，以筛选新的神经活性药物使用离子通量测量利用成像技术对各种离子，包括Ca2+和Na+。新型钙通道阻滞剂的潜在鉴定可能最终导致治疗干预的阐明，以实现神经保护，这可能应用于治疗缺血和其他类型的脑损伤。研究人员提议测试这种毒液以及其他阻滞剂的工作假设。为了验证这一点，将在各种模型制剂上测试分离的成分毒素的影响，包括小龙虾神经索（电生理测量）和单个神经元细胞（利用荧光成像技术测量离子通量和cAMP）。该项目将由夏威夷大学和约翰霍普金斯大学的研究人员进行综合协调合作。申请人的项目部分将侧重于独特成分毒素的生化分离及其对目标组织的电生理和形态影响，而合作部分将侧重于离子通量和次级信使系统效应的评估，特别强调钙和cAMP通量的测量。在这两个组成部分中测试的假设与实验设计密切相关，并将允许研究人员的互补专业知识以最大限度地生产和互利的方式得到应用。这项合作还将为夏威夷大学的学生和研究员提供充分的机会，让他们获得在这项研究工作中实施的基本神经科学技术方面的培训。

Venoms have historically proven to be a rich source of powerful neuroactive agents. Recent discovery of SNX-325, a selective blocker of class B (N-type) calcium channels, has provided clinicians with a novel agent for the treatment of intractable pain. Currently available calcium channel drugs, including the dihydropyridines, target channels are functionally and pharmacologically distinct from the peripheral L-type channels and the exploration of their therapeutic modulation is limited by the present lack of specific agonists and antagonists. Drugs targeted toward these channels would be useful, for example, in minimizing neuronal damage caused by excess calcium entry during periods of ischemia. Recent findings from the applicant's laboratory demonstrate that the most powerful of the Hawaiian water coelenterate venoms, Carybdea alata venom, contains at least three distinct activities. The general goal of the collaborative research proposed is to augment the ability of the applicant to screen for novel neuroactive agents using ion flux measurements utilizing imaging techniques for various ions including Ca2+ and Na+. Potential identification of novel calcium channel blockers may ultimately result in elucidation of therapeutic interventions to accomplish neuroprotection which may be applied in the treatment of ischemia and other types of brain injury. Studies are proposed to test the working hypothesis that this venom, as well as other blockers. To test this, the effects of isolated constituent toxins will be tested on various model preparations including crayfish nerve chord (electrophysiological measurement) and single neuronal cells (ion flux and cAMP measurements utilizing fluorescence imaging techniques). The project will be conducted as an integrated and coordinated collaboration between investigators at the University of Hawaii and Johns Hopkins University. The applicant's component of the project will focus on biochemical separation of unique constituent toxins and their respective electrophysiological and morphological effects upon target tissues, while the collaborating component will focus on the evaluation of ion flux and secondary messenger system effects, with particular emphasis on calcium and cAMP flux measurements. The hypotheses to be tested in both components are closely interrelated as are the experimental designs, and will allow the complementary expertise of the investigators to be applied in a maximally productive and mutually beneficial way. The collaboration will also provide ample opportunities for students and fellows at the University of Hawaii to obtain training in the basic neuroscientific techniques to be implemented in the conduct of this research effort.