COCAINE & FETAL CEREBRAL BLOOD FLOW AND METABOLISM

这项研究项目的主要目标是确定 可卡因引起的低氧血症，脑血管收缩，以及可能的 氧化代谢的增加可能在胎儿中结合在一起产生 胎脑组织严重缺氧可导致宫内脑组织缺氧 受伤。在成年人中，可卡因对血管的收缩作用已知 大脑循环。众所周知，可卡因通过以下方式引起胎儿低氧血症 减少子宫血流量；正常代偿性胎脑 可卡因的这些血管收缩作用可能会削弱血管扩张， 加剧组织缺氧。此外，可卡因可能会增加大脑 氧化代谢，这将进一步损害组织的氧合。 在长期准备好的胎羊中，血管导管将被放置在 胎儿动脉、静脉、上矢状窦和母体动脉 还有血管。将放置电极以记录胎儿 脑电、心电和肌电。大脑 血流量将用微球测量，大脑代谢将 要用菲克原理来研究。可卡因将被注入母亲体内 胎儿测定对胎儿动脉和矢状窦的影响 氧合作用、脑血流量、脑氧化和碳水化合物 新陈代谢和胎儿行为。 尽管可卡因是最受欢迎的非法药物之一，在 怀孕，到目前为止，关于可卡因对 胎儿生理学，可卡因对胎儿大脑的代谢影响，或 可卡因对胎儿行为的影响。拟议的研究假设 根据最近观察到的一种高水平的 脑部结构异常和小头畸形的发生率 接触可卡因的后代。这些研究将有助于 对可卡因所致脑损伤及对胎儿影响的认识 和新生儿的行为以及对婴儿生理的理解 胎脑循环与可卡因的药理作用 怀孕了。

The principal objective of this research project is to determine whether cocaine-induced hypoxemia, cerebral vasoconstriction, and possible increases in oxidative metabolism may combine in the fetus to produce severe fetal brain tissue hypoxia which could induce intrauterine brain injury. In adults, cocaine has known vasoconstrictive effects on the cerebral circulation. Cocaine is known to induce fetal hypoxemia by reducing uterine blood flow; the normal compensatory fetal cerebral vasodilation may be blunted by these vasoconstrictive effects of cocaine, exacerbating tissue hypoxia. In addition, cocaine may increase cerebral oxidative metabolism, which would further compromise tissue oxygenation. In chronically prepared fetal sheep, vascular catheters will be placed in fetal arteries, veins, and superior sagittal sinus and in maternal arteries and veins. Electrodes will be placed for recording fetal electroencephalogram, electrocardiogram, and electromyograms. Cerebral blood flow will be measured with microspheres and cerebral metabolism will be studied by the Fick principle. Cocaine will be infused into mother and fetus to determine the effects on fetal arterial and sagittal sinus oxygenation, cerebral blood flow, cerebral oxidative and carbohydrate metabolism, and fetal behavior. Although cocaine is one of the most popular illicit drugs used during pregnancy, to date very little is known regarding the effects of cocaine on fetal physiology, the metabolic effects of cocaine on the fetal brain, or the effects of cocaine on fetal behavior. The proposed studies assume particular clinical relevance in light of recent observations of a high prevalance of brain structural .abnormalities and microcephaly in cocaine-exposed offspring. These studies will contribute to the understanding of cocaine-induced brain lesions and cocaine effects on fetal and newborn behavior as well as to the understanding of the physiology of the fetal cerebral circulation and the pharmacology of cocaine during pregnancy.