ROLE OF CALCIUM IN ACRYLAMIDE NEUROTOXICITY

钙在丙烯酰胺神经毒性中的作用

• 批准号: 3251555
• 负责人: Richard Michael Lopachin
• 金额: $ 18.67万
• 依托单位: STATE UNIVERSITY NEW YORK STONY BROOK
• 依托单位国家: 美国
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-08-01 至 1994-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3251555
• 关键词: acrylamides; atomic absorption spectrometry; autoradiography; axon reaction; calcium; calcium channel; calcium channel blockers; cell osmotic pressure; cerebellum; chlorine; dorsal root; electron microscopy; electron probe spectrometry; elements; embryo /fetus; enzyme mechanism; laboratory rat; magnesium; mitochondria; myelin; neurotoxins; oxygen consumption; oxygen microelectrode; peripheral nervous system disorders; phosphatidylinositols; phospholipase C; phosphorylation; potassium; protein kinase; radiotracer; sciatic nerve; scintillation counter; sodium; sodium potassium exchanging ATPase; spinal cord; sulfur compounds; thin layer chromatography; tissue /cell culture

Despite 20 years of research, the mechanism by which acrylamide (ACR) produces central peripheral distal axonopathy remains poorly understood. Based on accumulating evidence, it is possible that perturbation of elemental homeostasis represents an important component of the mechanism of ACR neurotoxicity. The long-term goals of this research project are: (1) to determine whether subcellular elemental deregulation plays an important role in the manifestation of ACR nerve damage, and (2) to determine the biochemical lesion responsible for disruption of elemental homeostasis. Electron probe x-ray microanalysis (EPMA) used during the previous grant period showed that ACR disrupted elemental regulation and water content in several compartments of rat distal tibial nerve. Therefore, our first specific aim for the next grant period will be to expand our EPMA study of ACR neurotoxicity in rats. Concentrations of elements (NA, K, Cl, P, Ca, S, Mg) and water content will be determined in axoplasm, mitochondria and myelin of small, medium, and large diameter fibers and in, nodes of Ranvier, Schwann cell cytoplasm and extra-cellular space. To establish the spatio-temporal nature of altered elemental regulation in ACR neuropathy, the above morphological compartments will be analyzed in proximal and distal sciatic nerve and in tibial nerve. Such determinants will be made at several times during the development of neurotoxicity. The effects of ACR intoxication on the levels of elements and water in dorsal root ganglion and spinal cord will also be defined. Recently, we found that both protein phosphorylation and phosphoinositide turnover were increased in sciatic nerve of ACR-treated rats. To identify the mechanism by which ACR produces these effects three specific aims will be pursued. We will determine the site of altered phosphoinositide metabolism and protein phosphorylation in fractions of sciatic nerve. We will determine whether the activities of phospholipase C and protein kinase C (PKc) in sciatic nerve are affected by ACR administration. We will provide evidence for a biochemical link between increased phosphoinositide turnover and protein phosphorylation by comparing the levels of 1,2-diacylglycerol in sciatic nerves from control and ACR-treated rats. Several lines of evidence indicate that alterations in phosphoinositide turnover caused by ACR might be related to observed elemental disruption through altered modulation of membrane Na/K-ATPase activity. Accordingly, the activity of this enzyme will measured in sciatic nerve of ACR intoxicated rats and compared to that of control. The final specific aim is to conduct parallel studies with 2,5-hexanedione to determine whether biochemical and elemental changes associated with ACR are shared by other agents which cause a distal axonopathy. The proposed experiments should provide new information concerning the mechanism of experimental distal axonopathies and may have relevance to the pathogenesis and treatment of comparable acquired and inherited neuropathies in humans.

尽管研究了20年，但丙烯酰胺（ACR）的机制 产生的中央外周远端轴突病仍然很了解。 基于积累的证据，可能会扰动 元素稳态代表了该机制的重要组成部分 ACR神经毒性。 该研究项目的长期目标是：（1） 确定亚细胞元素放松管制是否重要 在ACR神经损伤的表现中的作用，（2）确定 生化病变负责破坏元素稳态。 电子探针X射线微分析（EPMA） 时期表明，ACR破坏了元素调节和水的含量 大鼠胫骨远端神经的几个隔室。 因此，我们的第一个 下一个赠款期的具体目的是扩大我们的EPMA研究 大鼠ACR神经毒性。 元素的浓度（Na，K，Cl，P，Ca， S，mg）和水含量将在轴突，线粒体和 小，中和大直径纤维的髓磷脂 Ranvier，Schwann细胞细胞质和细胞外空间。 建立 ACR神经病中元素调节改变的时空性质， 上述形态学室将在近端和 远端坐骨神经和胫骨神经。 将制定这样的决定因素 在神经毒性发展过程中的几次。 效果 在背根中的元素和水的水平上的ACR中毒 神经节和脊髓也将定义。 最近，我们发现 蛋白质磷酸化和磷酸肌醇周转率都增加了 在ACR处理的大鼠的坐骨神经中。 确定该机制 ACR会产生这些效果，将追求三个具体目标。 我们将 确定改变磷酸肌醇代谢和蛋白质的位点 坐骨神经级分的磷酸化。 我们将确定是否 磷脂酶C和蛋白激酶C（PKC）在坐骨神经痛中的活性 神经受ACR给药的影响。 我们将提供证据 增加磷酸肌醇周转和蛋白质之间的生化联系 通过比较坐骨神经痛中1,2-二酰基甘油的水平，磷酸化 来自对照和ACR治疗的大鼠的神经。 几条证据 表明由ACR引起的磷酸肌醇周转率的改变可能 通过改变的调制，与观察到的元素破坏有关 膜Na/K-ATPase活性。 因此，该酶的活性 将以ACR醉酒大鼠的坐骨神经进行测量 控制。 最终的具体目的是与 2,5-己二酮，以确定生化和元素是否变化 与ACR相关的ACR是由其他代理共享的，这会导致远端 轴突病。 拟议的实验应提供新信息 关于实验远端轴突病的机制，可能具有 与可比较的获得的发病机理和治疗相关， 人类的遗传神经病。