Ion Gradients And Metabolic Energy In Animal Tissue

摘要：工作灌注心脏中9种主要无机离子的梯度能量彼此接近平衡，细胞外相和细胞内相之间的电势和？ATP水解[1]。乙醇的代谢使肝细胞的静息电位从-28毫伏增加到-40毫伏。之前，我们证明了仅仅改变可用的底物就能改变？ G！使心脏的水力工作效率提高28% b[3]。由于任何类型的损伤都会引起细胞离子分布的刻板变化，其中细胞获得Na+，失去K+并膨胀，因此损伤的这些刻板变化可能通过简单地改变给予损伤或烧伤受害者的液体成分来逆转。我们继续展示了所有九种常见无机离子在细胞内相和细胞外相之间的梯度形成了一个多南接近平衡系统，将相之间的电位与ATP水解的能量联系起来。这些研究和我们早期批评现有肠外液体成分的研究的结果是，一个由医学研究院召集的小组，建议开始研究制造新的复苏液的可行性。

Summary: The energy of the gradients of the nine major inorganic ions in working perfused heart are in near equilibrium with each other, the electrical potential between extra- and intracellular phase and the ?'G!| of ATP hydrolysis [1]. The metabolism of ethanol increases the resting electrical potential of hepatocytes from -28 to -40 mV [2]. Previously, we showed that merely changing the substrate available altered the ?'G!| of ATP hydrolysis in heart and improved the efficiency of hydraulic work of heart by 28% [3]. Since injuries of any sort induce a stereotypic change in cellular ionic distributions wherein the cell gains Na+, loses K+ and swells, these stereotypic changes of injury can possibly be reversed by simple changes in the compositions of fluids administered to victims of injury or burns. We went on to show that the gradients of all nine common inorganic ions between intra and extracellular phases of a cell form a Donnan near equilibrium system relating the electrical potential between the phases to the energy of ATP hydrolysis [4] As a result of these studies and our earlier studies criticizing the composition of existing parenteral fluids [5] a panel convened by the Academy of Medicine, recommended that investigation of the feasibility of making new resuscitation fluids be initiated [6]. We have taken part in these studies sponsored by the Department of Defense since that time. The goal is to improve the standard treatment of hemorrhage and burns, which has not changed over the past 50 years. We had earlier shown that the d isomer of lactic acid, a component in Ringers Lactate, induced cardiac arrythmias in children undergoing resuscitation from burn and could induce fatal arrythmias in experimental animals [7]. In collaboration with the Naval Blood Research Laboratory, we designed and caused to be manufactured alternatives Ringer!|s solutions for use in resuscitation from hemorrhage in experimental animals. Tests of these newly manufactured fluids performed at USUHS have shown that resuscitation from hemorrhage with the standard high volume Ringer!|s lactate protocol leads to apoptosis in the lung 24 hours after hemorrhage and that this untoward effect can be avoided if Na D-?O-hydroxybutyrate is substituted for the D,L-lactate in such fluids [8]. Lung damage after resuscitation, so called DaNang lung was a leading cause of post surgical death during the Viet Nam war. Although not admittedly, during 2003, the US fluid manufacturers changed the composition of Ringer!|s lactate from D,L to L lactate. This change was not done through submission of new data to FDA, but rather through the expedient of changing the definition of lactate in the US Pharmacopeia from a substance without optical rotation, to one with optical rotation. The inclusion of L-lactate in parenteral fluids, while an improvement over fluids containing D,L-lactate, is not optimum. Conditions requiring resuscitation are almost inevitably associated with hypoxia and lactic acidosis. Additional infusion of L-lactate worsens this condition and adds to the blockade of glycolysis, the major source of energy generation during periods of hypoxia as has been shown in studies by collaborators [9]. It is our opinion that resuscitation fluids containing D-?O-hydroxybutyrate in place of L-lactate are preferable. In collaboration with the Naval Blood Laboratory, we are attempting to design and prepare such fluids made under cGMP conditions for testing in human subjects. SIGNIFICANCE OF THIS WORK TO THE PROGRAMS OF THIS INSTITUTE Ingestion of alcohol reduces the free [NAD+]/[NADH] ratio in cytoplasm of liver as does intravenous administration of l-lactate. Therefore this work has some significance to the work of this institute. However, this work is of greater significance to medical and surgical treatments in general particularly to the treatment of those engaged in combat or subject to injury from mass disasters.