POSTNATAL DEVELOPMENT OF PERIPHERAL CIRCULATORY FUNCTION

人们早就知道，成年人的血液循环是由 神经和局部组织机制之间的相互作用。 但一个基本上未解决的 问题是，在出生后的发育过程中， 有效 在出生后发育的时间过程中的差异， 外周神经血管收缩和局部血管扩张系统 血流的调节正在麻醉的猪中进行研究， 不同年龄 使用生理学和药理学方法。 动脉压力由应变传感器记录，流量由 非空心电磁换能器。 三个血管床 被选中进行研究。 神经活动的作用是在实验中评估 涉及交感神经传出纤维的去神经支配和刺激。 通过灌注压的阶跃变化来评估自动调节控制 通过压缩隔膜下方的主动脉， 血管阻力的延迟变化作为存在和 血流自动调节范围。 肾和股动脉实验 流通已经完成。 正在进行的肠道研究 循环已经发展到包括比较回肠和 空肠血管床，其向具有 不同的运输功能。 在拟议继续执行 在这次调查中，将执行压力控制协议， 对节后交感神经去神经支配和神经刺激的反应 将被确定，并响应单次注射和连续 i.a.将评估血管活性化合物。 的影响 后者将根据灌注压的变化进行评估 在回肠和空肠段的控制流灌注期间， “自动调节逃避”“在正在进行的和新的实验中， 神经和局部介导的反应之间的差异将是 通过对发病率和幅度的统计分析， 影响，并将寻求年龄组之间的差异。 的 长期目标是检查生理期间的局部循环反应 然后应力将是局部血流分布（在肾脏之间， 后肢和回肠或空肠）和血流自动调节 实验诱导的局部血流需求增加， 增加骨骼肌工作或肠道活动。

It has long been known that the adult circulation is controlled by interplay among neural and local tissue mechanisms. But a largely unsolved question is when during postnatal development does each mechanism before effective. Differences in the time-course of postnatal development of the peripheral neural vasoconstrictor and local vasodilator systems in the regulation of blood flow are being investigated in anesthetized swine of various ages. Both physiologic and pharmacologic approaches are used. Arterial pressure is registered by strain gauge transducer, and flow by non-cannulating electromagnetic transducer. Three vascular beds have been selected for study. The role of neural activity is assessed in experiments involving denervation and stimulation of sympathetic efferent fibers. Autoregulatory control is assessed by step-changes in perfusion pressure via compression of the aorta below the diaphragm to provide immediate and delayed changes in vascular resistance as evidence for the presence and range of blood flow autoregulation. Experiments on the renal and femoral circulations have been completed. Ongoing research on the intestinal circulation has progressed to include experiments comparing the ileal and jejunal vascular beds, which provide blood to intestinal segments having somewhat different transport functions. In the proposed continuation of this investigation, controlled-pressure protocols will be carried out, responses to postganglionic sympathetic denervation and nerve stimulation will be determined, and responses to single injections and continuous infusion i.a. of vasoactive compounds will be evaluated. The effects of the latter will be assessed in terms of alterations in perfusion pressure during controlled-flow perfusion of ileal and jejunal segments, and of "autoregulatory escape." In both the ongoing and new experiments, differences between neurally and locally mediated responses will be examined at each age by statistical analysis of the incidence and magnitude of effects, and differences between age groups will be sought. The long-term goal to examine regional circulatory responses during physiologic stress will then be regional blood flow distribution (among kidney, hindlimb, and ileum or jejunum) and blood flow autoregulation during experimentally induced in creases in the local demand for blood flow, by increasing skeletal muscle work or intestinal activity.