POSTNATAL MATURATION OF CARDIOVASCULAR REGULATORY SYSTEM

心血管(CV)出生后发育的时间进程 正在从以下角度研究监管机制： 监管系统的流出。三个具体目标 正在研究：1)与年龄有关的同情性差异 (符号)活动(传出放电和血浆) 儿茶酚胺水平)，2)解剖和生理 自主调节的后天发育特点 (来自心脏传出神经和心脏的记录 迷走运动神经元及其荧光示踪剂在解剖学中的应用 节前副交感神经和节后神经的定位 投射到心脏的交感神经元)，3)测定 先前确定的中枢神经系统对化学刺激的CV反应 网站。录音将从传出的符号活动中获得 (内脏、颈、肾)、传出膈神经放电 (呼吸节律发生器监护仪：RRG)、心脏迷走神经和 腹外侧核的交感纤维、单核模糊， 主动脉压、EKG、局部血流量(尤其是肾脏、 肠系膜上段)和适当的标记脉冲。年龄- 不同脑区传入放电变化的相关效应 感受器，如压力感受器，心肺，肺伸展， 将对CV调节系统上的化学感受器进行评估。 症状出院中常见的周期性及其相关周期性 心动周期(由EKG表示)或RRG 互相关和功率谱分析显示， 特别是功率谱等价性和相干性的测试。 自主神经对刺激中枢神经系统的诱发反应 脑干中的血管活性部位和心脏部位，尤其是 不同符号运动神经元池的激活顺序，将 将被获得。将确定结果的年龄相关性 在6个年龄组进行统计学分析。结果将有助于我们的 对宫外两种循环调节的认识 环境与新生儿CV调节程度的关系 功能。年龄相关发育差异的证据 交响乐节奏生成系统以及与交响乐团的互动 RRG具有临床意义，因为对婴儿疾病的研究， 例如，小岛屿发展中国家、呼吸暂停和伴随的心动过缓，表明他们的 紧密的时间和功能关系。信息将会是 以进一步阐明对压力的反射调节， 例如，低氧、高碳酸血症，尤其与大多数人有关 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.