BIOCHEMICAL EVOLUTION OF ISCHEMIC BRAIN DAMAGE

这项调查的目的是确定组织酸中毒 在缺血性损伤的发展中起关键作用，如果是这样的话，通过 哪些生化机制。使用可逆的、单边的 在小鼠缺氧缺血时，我们首先会发展出一种区域性的， 脑组织pH值的定量测定方法。第二，脑内pH值的缺血性改变 与缺氧性脑缺血时乳酸的蓄积有关 并伴随着缺血后能量代谢的恢复。第三，酸碱度变化 在缺氧-缺血期间将被改变(A)通过给予二氧化碳和(B) 通过部分抑制糖酵解途径来改变 能量代谢的恢复。最后，糖酵解的缺血性改变。 除乳酸以外的中间体将在葡萄糖处理后被测定 动物检测与酸中毒无关的有害变化。这个 第二个主要目标是确定哪些生化过程是 受酸中毒/葡萄糖预处理的影响。因为NADH是酸不稳定的，我们 将测量大脑中NADH、NAD+及其降解产物的水平 采用酶促方法和高效液相色谱(HPLC)。 此外，我们将尝试通过以下方式更改NAD池的大小 注射前驱物烟酰胺和假前驱物， 6-氨基烟酰胺。酸中毒/葡萄糖预处理对脑的影响 腺苷、鸟苷、尿嘧啶和胞嘧啶核苷酸水平的变化 缺氧-缺血将用高效液相色谱法测定。最后，降解剂 缺氧缺血性脑组织中酸性磷酸酶活性的测定 使用体外和体内两种方法。

The goal of this investigation is to determine whether tissue acidosis plays a critical role in the development of ischemic damage and, if so, by which biochemical mechanisms. Using a model of reversible, unilateral hypoxia-ischemia in the mouse, we will first develop a regional, quantitative method for brain pH. Second, ischemic alterations of brain pH will be correlated with the accumulation of lactate during hypoxia-ischemia and with postischemic recovery of energy metabolism. Third, the pH changes during hypoxia-ischemia will be modified (a) by administering CO2 and (b) by partially inhibiting the glycolytic pathway in order to alter the recovery of energy metabolism. Finally, the ischemic change in glycolytic intermediates other than lactate will be determined in glucose-pretreated animals to detect deleterious alterations not related to acidosis. The second major aim is to identify the biochemical processes which are affected by acidosis/glucose-pretreatment. Because NADH is acid-labile, we will measure brain levels of NADH, NAD+, and their degradation products using enzymatic methods and high performance liquid chromatography (HPLC). In addition, we will attempt to alter the size of the NAD pool by administering the precursor, nicotinamide, and a false precursor, 6-amino-nicotinamide. The effect of acidosis/glucose-pretreatment on brain levels of Adenyl, Guanyl, Uridyl, and Cytidyl Nucleotides during and after hypoxia-ischemia will be determined using HPLC. Finally, the degradative activity of acid phosphatase will be assayed in hypoxic-ischemic brain using both in vitro and in vivo methods.