CONTROL OF INTESTINAL OXYGENATION DURING POSTNATAL LIFE

该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。代谢活动 与胎儿或成人肠道相比，新生儿肠道内的蛋白质增加， 肠道高摄氧率特征证明了这一点 这个年龄的人。局部血流调节的代谢理论假设 组织代谢率与局部化疗疗效之间的密切联系 对氧气运输的控制；这一理论因此预测了 局部血管控制在新生儿肠道中应该是例外的。 矛盾的是，这个实验室的初步研究表明 新生儿肠道对氧气运输的局部控制能力不如 来自年长动物的肠道。相应地，这一工作假说 GRANT应用如下：局部控制肠道氧气 运输在出生后的早期是无效的；这一调节 机制不能维持氧气的运输速度 与组织的氧化需求相一致。为了检验这一假设， 这项建议的具体目标是：1.确定是否降低 基线摄氧量影响血流与血流量的关系 摄氧量；2.量化肠道交换血管的自动调节 在1日龄、3日龄、7日龄、14日龄和30日龄猪的肠道中；3.确定是否降低 基线肠道供氧影响压力-流量治疗效果 3日龄和30日龄猪肠道的自身调节；4.量化 去甲肾上腺素、加压素和血管紧张素的自我调节逃逸 取3日龄和30日龄猪的肠组织；5.测定 心源性休克对大鼠肠道血流动力学和氧合功能的影响 3日龄和30日龄猪肠道；6.量化餐后血流动力学 自发性摄入适龄食物后的事件3，7， 14和30日龄清醒、独立的猪；7.测定 从出生到出生后第3天持续肠道禁食的影响 压力-流量自动调节的效果。这些实验将 提供有关肠道发育生理学的新数据 氧运输，一个对出生后肠道适应至关重要的过程，因此对 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.