NEUROBIOLOGY OF RESPIRATION IN DEVELOPING AMPHABIAN

自发呼吸节律的发展和维持对所有脊椎动物的生存都是至关重要的。呼吸节律发生的神经元的精确位置，以及呼吸性婴儿猝死综合症(SID)和睡眠呼吸暂停(睡眠呼吸暂停)的传入和传出连接，这些疾病困扰着发育谱的两端。为了研究中枢呼吸模式生成和化学接收所必需的神经底物的发育，开发了牛蛙蝌蚪Rana catesbeiana的体外脑干制剂。这项拟议的研究将进一步了解产生和维持自发的、有节奏的呼吸运动输出所必需的神经成分。此外，将描述中枢和外周化学感受器输入呼吸中枢模式发生器(CPG)在发育过程中的意义。具体地说，实验设计如下：1.在发育过程中，确定中枢和外周呼吸化学感受器输入对中枢呼吸模式生成和运动输出的相对贡献。2.明确在脊椎动物发育过程中负责鳃和肺呼吸模式产生的神经元的准确位置。3.在发育中的脊椎动物中，开始确定鳃和肺呼吸模式发生的细胞、离子、生物物理性质和网络连接。呼吸相关神经元的完整神经和细胞内记录将用于半完整和体外超融合蝌蚪脑干准备。半完整的脑干/鳃弓制剂将用于检测中枢和外周化学感受器刺激的影响；所有其他研究将使用体外脑干制剂。荧光染料的离子导入将被用来创建呼吸运动神经元、中间神经元和候选中枢模式生成神经元的投射图。将进行各种神经递质激动剂和拮抗剂的沐浴应用，这些激动剂和拮抗剂被证明是脊椎动物呼吸节律的原因，以确定它们对鳃和肺运动模式的影响。将对脑干进行薄片准备，以阐明鳃和肺模式生成神经元的准确位置。每项研究的发展方面将通过对发育各个阶段的蝌蚪进行上述实验来解决。

The development and maintenance of a spontaneous respiratory rhythm is essential for the survival of all vertebrates. The precise location of neurons responsible for respiratory rhythmogenesis , as well as the afferent and efferent connections of the respiratory Sudden Infant Death Syndrome (SIDS) and sleep apnea, disorders which afflict both ends of the developmental spectrum, An in vitro brainstem preparation of the bullfrog tadpole Rana catesbeiana has been developed in order to investigate the development of the neural substrates essential to central respiratory pattern generation and chemoreception. The proposed research will further the understanding of the neural components necessary to produce and maintain spontaneous, rhythmic respiratory motor output. In addition, the significance of both central and peripheral chemoreceptor input to the respiratory central pattern generator (CPG) during development will be described. Specifically, experiments have been designed: 1. To determine during development the relative contribution both of central and peripheral respiratory chemoreceptor input on central respiratory pattern generation and motor output. 2. To define the precise location of neurons responsible for both gill and lung respiratory pattern generation in the developing vertebrate. 3. To begin to determine, in the developing vertebrate, the cellular, ionic, biophysical properties and network connections underlying gill and lung respiratory pattern generation. Both whole nerve and intracellular recordings from respiratory-related neurons will be employed in semi-intact and in vitro superfused tadpole brainstem preparations. A semi-intact brainstem/gill arch preparation will be used to examine the influence of both central and peripheral chemoreceptor stimulation; all other studies will use the in vitro brainstem preparation. lontophoresis of fluorescent dyes will be used to create maps of the projections of respiratory motor neurons, interneurons, and candidate central pattern generation neurons. Bath application of various neurotransmitter agonists and antagonists documented to be responsible for respiratory rhythmicity in vertebrates will be performed in order to characterize their effects on gill and lung motor patterns. Thin slice preparations of the brain stem will be performed to elucidate the precise location of gill and lung pattern generating neurons. The developmental aspect of each study will be addressed by performing the above experiments on tadpoles from all stages of development.