HYPOXIC EFFECTS ON MAMMALIAN RESPIRATORY NEURAL NETWORK

描述(改编自申请人的摘要)： 每年都有许多受害者因缺氧和缺氧而遭受脑损伤。 侮辱。为了了解这个项目潜在的细胞机制 研究缺氧对小鼠中枢呼吸系统的影响。 这种网络可以在脑干切片制剂中分离出来， 自发地产生呼吸节律活动。获取的切片 一周以上的小鼠对缺氧的反应非常相似 作为化学传入的失神经，但其他方面是完整的呼吸系统。 因此，该制剂将作为模型来研究 中枢呼吸系统的缺氧反应。研究计划 在网络、细胞和分子层面上使用各种 电生理学和药理学技术。额外的和 细胞内记录技术以及标测和损伤 进行实验以识别和表征不同的 呼吸系统的一部分：一个网络，在所谓的前- Boetzinger复合体(PBC)，负责产生正常 呼吸及其缺氧诱导的与神经网络的相互作用 这可能是气喘吁吁的原因。提出了一个模型，该模型是如何 这些神经网络之间的相互作用导致了双相 对缺氧的反应，包括最初的增强，抑郁， 呼吸暂停，然后气喘吁吁。为了了解潜在的神经机制 这种双相反应，整个细胞，细胞附着，向外和 采用自内向外膜片钳记录技术。计划中的 实验的目的是更详细地描述直接缺氧 对不同钙、钾通道亚型的影响。然而， 这一描述将被补充到分析如何 细胞的直接变化间接影响其他细胞的激活 的生成涉及的细胞属性 呼吸节律。因此，只有可能理解双相 以综合的、多层次的方法作出反应。一个假设的模型是 提出了抑制N型钙通道如何导致 间接导致突触传递和开放概率的变化 依赖钙离子的钾通道。在此模型中，这些 改变导致Ih电流的激活减少，这 会改变呼吸节律的产生机制。检视 这一假设，这些蜂窝和网络事件的级联将 被分析。对这些神经机制的更好理解将 为更合理地对待各种 导致呼吸停止的呼吸障碍，如 睡眠呼吸暂停、新生儿复发性呼吸暂停和婴儿猝死 综合症。

DESCRIPTION (Adapted from the applicant's abstract): Every year numerous victims suffer brain damage from hypoxic and anoxic insults. To understand the underlying cellular mechanisms this project examines the anoxic effects on the central respiratory network of mice. This network can be isolated in a brainstem slice preparation which generates spontaneously respiratory rhythmic activity. Slices obtained from mice older than one week respond to anoxia in a very similar way as the chemoafferent-denervated but otherwise intact respiratory system. Therefore this preparation will be employed as a model to study the anoxic response of the central respiratory network. The research plan bridges the network, cellular and molecular level using various electrophysiological and pharmacological techniques. Extra and intracellular recording techniques as well as mapping and lesion experiments are performed to identify and characterize different portions of the respiratory system: a network in the so called pre- Boetzinger complex (pBC) which is responsible for generating normal respiration and its anoxia-induced interaction with a neural network which may be responsible for gasping. A model is proposed how the interaction between these neuronal networks leads to the biphasic response to anoxia, which includes an initial augmentation, depression, apnea and then gasping. To understand the neural mechanisms underlying this biphasic response, whole cell, cell attached, outside-out and inside-out patch clamp recording techniques are used. The planned experiments aim at characterizing in great detail the direct anoxic effects on different calcium and potassium channel subtypes. However, this characterization will be supplemented with an analysis of how these direct cellular changes affect indirectly the activation of other cellular properties that are involved in the generation of the respiratory rhythm. Thus, it is only possible to understand the biphasic response in an integrated multi-level approach. A hypothetical model is proposed as to how a suppression of the N-type calcium channel leads indirectly to changes in synaptic transmission and the open probability of calcium-dependent potassium channels. In this model, these alterations result in a decreased activation of the Ih current which will alter the mechanisms of respiratory rhythm generation. To examine this hypothesis, the cascade of these cellular and network events will be analyzed. A better understanding of these neural mechanisms will provide an important foundation for a more rational treatment of various breathing disorders that result in a cessation of breathing such as sleep apnea, recurrent apnea of the newborn and sudden infant death syndrome.