CADMIUM, COBALT, NICKEL EFFECT ON SIGNAL TRANSDUCTION IN SHARK RECTAL GLAND

镉、钴、镍对鲨鱼直肠腺信号转导的影响

• 批准号: 6271005
• 负责人: JOHN N FORREST
• 金额: $ 3.25万
• 依托单位: MOUNT DESERT ISLAND BIOLOGICAL LAB
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-04-01 至 1999-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6271005
• 关键词: Xenopus oocyte; biological signal transduction; cadmium; calcium channel; cellular polarity; chlorine; cobalt; enzyme activity; hormone regulation /control mechanism; inositol phosphates; ion transport; membrane potentials; metal poisoning; molecular cloning; nickel; phosphodiesterases; protein kinase C; protein transport; salt gland; saltwater environment; sharks; tissue /cell culture; toxicant interaction

This application seeks support through the Center for Membrane Toxicology Studies (CMTS) at the Mount Desert Island Biological Laboratory for studies on the effects of three heavy metals (cadmium, cobalt and nickel) on signal transduction pathways of hormones regulating chloride secretion in the shark rectal gland. The shark rectal gland is a homogenous, single cell type, highly specialized epithelium that is a model system for hormone regulated chloride secretion. Our hypothesis is that the toxic effects of heavy metals results from interactions at different specific sites of stimulatory as opposed to inhibitory hormonal signal transduction pathways. We have determined that cadmium reversibly blocks receptor-mediated inhibition of chloride secretion and that a major component of this effect occurs by a novel and unexpected mechanism- and augmentation of the response to stimulatory hormones. We will determine the specific site(s) of this metal-protein interaction by distinguishing between effects of cadmium on (a) an extracellular receptor for Cd mediating activation of inositol triphosphates and release of intracellular calcium; (b) direct effects on specific isozyme of cyclic nucleotide phosphodiesterases; and (c) a post-receptor/kinase mechanism- translocation of DFTR-chloride channels from an intracellular site to the apical plasma membrane. In contrast to Cd, cobalt and nickel inhibit VIP and forskolin stimulated chloride secretion in the perfused rectal gland. In collaboration with others in the center we will determine the protein interactive site(s) of these metals and distinguish between toxic effects on the calcium messenger system and direct actions on apical DFTR channels. Studies will be carried out in the in vitro perfused rectal gland, in primary culture monolayers of rectal gland cells, and in Xenopus oocytes expressing the DFTR chloride channel.

该应用程序寻求膜毒理学中心的支持 在山漠岛生物实验室进行的研究（CMTS） 三种重金属（镉、钴、镍）影响的研究 调节氯离子分泌的激素信号转导途径的研究 在鲨鱼的直肠腺中。鲨鱼直肠腺是一个同质的、单一的 细胞类型，高度特化的上皮细胞，是一个模型系统 激素调节氯离子分泌。 我们的假设是有毒物质 重金属的影响是不同特定条件下相互作用的结果 sites of stimulatory as opposed to inhibitory hormonal signal 转导途径。 我们已经确定镉可逆地阻断 受体介导的氯离子分泌抑制作用 这种效应的组成部分是通过一种新颖且意想不到的机制发生的——并且 增强对刺激性激素的反应。 我们将确定 通过区分这种金属-蛋白质相互作用的特定位点 镉对 (a) 细胞外镉受体的影响 介导肌醇三磷酸的活化和释放 细胞内钙； (b) 对环状特定同工酶的直接影响 核苷酸磷酸二酯酶； (c) 后受体/激酶机制- DFTR-氯离子通道从细胞内位点易位至 顶端质膜。 与 Cd 相比，钴和镍抑制 VIP 毛喉素刺激灌注直肠腺中的氯离子分泌。 与中心的其他人合作，我们将确定蛋白质 这些金属的相互作用位点并区分毒性作用 对钙信使系统的影响以及对心尖 DFTR 的直接作用 渠道。 研究将在体外灌注直肠进行 腺，在直肠腺细胞的原代培养单层中，以及 表达 DFTR 氯离子通道的非洲爪蟾卵母细胞。