CONTROL OF INTESTINAL OXYGENATION DURING POSTNATAL LIFE

本项目的目标是研究局部血管控制， 出生后发育过程中的肠道氧合。代谢活性 与胎儿或成人肠道相比， 如肠氧摄取特征的高速率所证明的 在这个年龄。局部血流调节的代谢理论假设 组织代谢率与局部治疗功效之间的密切联系 控制氧气运输;这一理论因此预测， 新生儿肠道局部血管控制异常。 奇怪的是，这个实验室的初步研究表明， 新生儿的肠道局部控制氧运输的能力比 老动物的肠子因此，这一工作假设 资助申请如下：肠氧局部控制 运输在出生后早期是无效的;这种调节 机制不能维持氧气运输的速率 与组织的氧化需求相一致。为了验证这个假设， 这项建议的具体目标是：为了确定是否降低 基线摄氧量影响血流量和 氧摄取; 2.定量肠交换血管的自动调节 在1、3、7、14和30日龄猪小肠中;为了确定是否降低 基线肠氧输送影响压力-流量的功效 3日龄和30日龄猪小肠的自身调节; 4.量化 去甲肾上腺素、加压素和血管紧张素的自身调节逃逸 3日龄和30日龄猪小肠; 5.确定 心源性休克对小肠血流动力学和氧合的影响 3日龄和30日龄猪小肠;定量餐后血流动力学 在3，7， 14日龄和30日龄清醒的独立猪; 7.确定 从出生到出生后第3天持续肠内禁食对 压力-流量自动调节的功效。这些实验将 提供了关于肠道发育生理学的新数据， 氧气运输，这是一个对出生后肠道适应至关重要的过程， 有机体的生存。

The goal of this project is to investigate local vascular control of intestinal oxygenation during postnatal development. Metabolic activity within newborn intestine is increased in comparison to fetal or adult gut, as evidenced by the high rate of intestinal oxygen uptake characteristic of this age. The metabolic theory of local blood flow regulation postulates an intimate link between tissue metabolic rate and the efficacy of local control of oxygen transport; this theory thus predicts that the efficacy of local vascular control should be exceptional in newborn gut. Paradoxically, preliminary studies in this laboratory have suggested that newborn intestine is less capable of local control of oxygen transport than intestine from older animals. Accordingly, the working hypothesis of this grant application is as follows: Local control of intestinal oxygen transport is ineffective during early postnatal life; this regulatory mechanism is not capable of maintaining oxygen transport at a rate consistent with the oxidative needs of the tissue. To test this hypothesis, the specific aims of this proposal are: 1. To determine if lowering base-line oxygen uptake affects the relationship between blood flow and oxygen uptake; 2. To quantify autoregulation of intestinal exchange vessels in 1, 3, 7, 14 and 30 day old swine intestine; 3. To determine if lowering base-line intestinal oxygen delivery affects the efficacy of pressure-flow autoregulation in 3 and 30 day old swine intestine; 4. To quantify autoregulatory escape from norepinephrine, vasopressin and angiotensin in intestine from 3 and 30 day old swine intestine; 5. To determine the effects of cardiogenic shock on intestinal hemodynamics and oxygenation in 3 and 30 day old swine intestine; 6. To quantify postprandial hemodynamic events following spontaneous ingestion of an age-appropriate meal in 3, 7, 14 and 30 day old conscious, free-standing swine; 7. To determine the effect of sustained enteral fasting from birth through postnatal day 3 on the efficacy of pressure-flow autoregulation. These experiments will provide novel data regarding the developmental physiology of intestinal oxygen transport, a process vital to postnatal gut adaptation, and thus to survival of the organism.