DEVELOPMENTAL NEUROTOXICITY OF METALLIC MERCURY

描述：(改编自《调查者摘要》)金属汞，a 神经毒物通常被视为一种职业危害，是一种更普遍的 对环境也有危害。尽管我们知道很多关于它的信息 对成年人的影响，我们对其对发育中的大脑的影响的了解是 支离破碎。这种信息鸿沟令人不安。(1)中国的许多女性 工人暴露在汞蒸气中。(2)许多，也许是大多数女性都有 牙科汞合金填充物。它们会释放出汞蒸气。母体组织和 胎儿水平与填充物的数量相关。(3)水星是一种 室内环境中更常见的污染物比人们普遍认识的要多。 由于其物理性质，它可以潜伏而不被发现，并继续 蒸发掉。(4)年幼的儿童更容易受到汞的影响 毒性大于成人；粉红病综合征是一个童年 痛苦。(5)有机汞化合物对大脑有很强的干扰作用 开发；一些权威人士认为，它向无机物的转变 脑细胞中的形态是导致中毒的机制。(6) 致力于神经行为影响的实验文献由一个 几项研究。提高我们评估风险的能力 金属汞对发育中的大脑，我们打算暴露两个孕妇 大鼠和新生儿对汞蒸气的反应。怀孕的老鼠会暴露在空气中， 30微克/立方米，100微克/立方米，OSHA允许水平，以及300 微克/立方米。新生大鼠将暴露在空气中，10，30和100 微克/立方米。暴露将持续两个小时。不同的级别是 根据报告显示，产前的敏感度存在很大差异 以及新生儿的暴露。母犬和幼犬的血液水平将被监测，以及 组织分析，特别是脑组织分析，将在选定的时间进行。至 确定发育暴露的功能后果，三个 将分析行为端点：(1)声学惊吓反应， 它将提供习惯化、感觉功能障碍和 对声音的总神经肌肉反应模式。(2)自发活动 大鼠的活动性，这是神经毒性的一个常见指标。(3)收购 时间表控制的操作行为。组织化学技术将是 用于绘制脑汞沉积的定位图。

DESCRIPTION: (Adapted from the Investigator's Abstract) Metallic mercury, a neurotoxicant usually viewed as an occupational hazard, is a more general environmental hazard as well. Although we know a great deal about its effects in adults, our knowledge of its impact on the developing brain is fragmentary. This information gap is disquieting. (1) Many women in the work force are exposed to mercury vapor. (2) Many, perhaps most, women have dental amalgam fillings. These emit mercury vapor. Maternal tissue and fetal levels are correlated with the number of fillings. (3) Mercury is a more common contaminant of indoor environments than is generally recognized. Because of its physical properties it can lurk undetected and continue to evaporate. (4) Young children are considerably more vulnerable to mercury toxicity than adults; the syndrome of Pink Disease is a childhood affliction. (5) Organic mercury compounds are potent disrupters of brain development; some authorities believe that its conversion to the inorganic form in brain cells is the toxic mechanism responsible. (6) The experimental literature devoted to neurobehavioral effects consists of a handful of studies. To enhance our ability to evaluate the risks of metallic mercury to the developing brain, we intend to expose both pregnant rats and neonates to mercury vapor. Pregnant rats will be exposed to air, 30 ug/cubic meter, 100 ug/cubic meter, the OSHA permissible level, and 300 ug/cubic meter. Neonatal rats will be exposed to air, 10, 30, and 100 ug/cubic meter. Exposure will last two hours. The different levels are based on reports indicating widely different sensitivities between prenatal and neonatal exposures. Dam and pup blood levels will be monitored, and tissue assays, especially of brain, will be conducted at selected times. To determine the functional consequences of developmental exposure, three behavioral endpoints will be assayed: (1) The acoustic startle response, which will provide measures of habituation, sensory dysfunction, and the total neuromuscular response pattern to sound. (2) Spontaneous locomotor activity in the rats, a common index of neurotoxicity. (3) Acquisition of schedule-controlled operant behavior. Histochemical techniques will be deployed to map localization of brain mercury deposits.