POSTNATAL MATURATION OF CARDIOVASCULAR REGULATORY SYSTEM

心血管（CV）出生后发育的时间过程 目前正在从以下角度研究调节机制： 调节系统的传出流出。 三个具体目标 1）年龄相关的交感神经系统差异 （SYMP）活动（传出放电和血浆 儿茶酚胺水平），2）解剖和生理 自主神经调节的生后发育特点 心脏的（心脏传出神经和心脏 迷走运动神经元和荧光示踪剂在解剖学上的应用 节前副交感神经和节后神经的定位 SYMP神经元投射到心脏），3）确定 CV对先前确定的CNS化学刺激的反应 网站. 将从传出SYMP活动中获得记录 （内脏、颈部SYMP、肾脏）、传出膈神经放电 （呼吸节律发生器监测器：RRG）、心脏迷走神经和 SYMP纤维，腹外侧核疑核的单神经元， 主动脉压、EKG、局部血流（特别是肾， 上级肠系膜）和适当的标记脉搏。 年龄- 各种传入放电改变的相关影响 受体，例如，压力感受器，心肺，肺伸展， 将评估CV调节系统上的化学感受器。 SYMP放电中常见的周期性及相关周期性 心动周期（由EKG指示）或RRG正在 通过互相关和功率谱分析显示， 特别是功率谱等效性和相干性的测试。 自主神经对中枢刺激的诱发反应 脑干中的血管活性和心脏部位，特别是 不同SYMP运动神经元池的激活顺序，将 获得。 将确定结果的依赖性 在6个年龄组中， 结果将有助于我们 了解循环调节和子宫外 环境和新生儿CV的调节程度 功能 年龄相关的发展差异的证据 的SYMP节奏产生系统和相互作用， RRG具有临床意义，因为对婴儿疾病的研究， 例如，在一个实施例中，婴儿猝死综合征，呼吸暂停和伴随的心动过缓，表明他们的 密切的时间和功能关系。 信息将 以进一步阐明对压力的反射调节， 例如，在一个实施例中，缺氧、高碳酸血症，尤其与大多数 儿童生命中的脆弱时期。

The time course of postnatal development of cardiovascular (CV) regulatory mechanisms is being studied from the viewpoint of efferent outflow of the regulatory system. Three specific aims are being pursued: 1) age-related differences in sympathetic (SYMP) activity (both efferent discharge and plasma catecholamine levels), 2) anatomical and physiological characteristics of postnatal development of autonomic regulation of the heart (recordings from cardiac efferent nerves and cardiac vagal motoneurons and use of fluorescent tracers for anatomical localizations of preganglionic parasympathetic and postganglionic SYMP neurons projecting to the heart), 3) determination of the CV responses to chemical stimulation at previously identified CNS sites. Recordings will be obtained from efferent SYMP activity (splanchnic, cervical SYMP, renal), efferent phrenic discharge (monitor of respiratory rhythm generator:RRG), cardiac vagal and SYMP fibers, montoneurons in ventrolateral nucleus ambiguous, aortic pressure, EKG, regional blood flows (particularly renal, superior mesenteric) and appropriate marking pulses. The age- related effects of alterations in afferent discharge from various receptors, e.g., baroceptor, cardiopulmonary, lung stretch, chemoceptors on the CV regulatory system will be evaluated. Common periodicities in SYMP discharge and periodicities related to the cardiac cycle (indicated by EKG) or RRG are being revealed by cross correlation and power spectral analyses, particularly tests for power spectral equivalence and coherence. Evoked responses of autonomic nerves to stimulation of CNS vasoactive and cardiac sites in the brain stem, especially the sequence of activation of different SYMP motoneuron pools, will be obtained. Age-dependency of results will be determined statistically in 6 age groups. The results will contribute to our understanding of both circulatory adjustements to extrauterine environment and to the degree of regulation of neonatal CV function. Evidence of age-related differences in the development of the SYMP rhythm generating systems and interactions with the RRG is clinically significant because studies of infnat diseases, e.g., SIDs, apnea and accompanying bradycardia, indicate their close temporal and functional relationship. Information will be obtained to further elucidate the reflex adjustments to stresses, e.g., hypoxia, hypercapnia, relevant especially to the most vulnerable period in the life of the child.