title: Relationship between cerebral interstitial levels of amino acids and phosphorylation potential during secondary energy failure in hypoxic-ischemic newborn piglets.
abstract: The aim of this study was to determine the validity of the hypothesis that excitatory amino acids are related to phosphorylation potential during primary and secondary cerebral energy failure observed in asphyxiated infants. We report here the results of experiments using newborn piglets subjected to severe transient cerebral hypoxia-ischemia followed by resuscitation. We examined cerebral energy metabolism by phosphorus nuclear magnetic resonance spectroscopy and changes in levels of amino acid neurotransmitters in the cortex by microdialysis before, during, and up to 24 h after the hypoxic-ischemic insult. The concentrations of aspartate, glutamate, taurine, and gamma-aminobutyric acid were significantly elevated during the hypoxic-ischemic insult compared with prebaseline values. Shortly after resuscitation, glutamate, taurine, and gamma-aminobutyric acid concentrations decreased but then began to increase again. These secondary elevations were greater than the primary elevations. A negative linear correlation was found between primary interstitial levels of glutamate and taurine and minimum values of phosphocreatine/inorganic phosphate during the secondary energy failure. The cerebral energy state depended on the time course of changes in excitatory amino acids, suggesting that amino acids play distinct roles during the early and delayed phases of injury.
authors: Maternal and Perinatal Center, Kagawa Medical University, Mikicho 1750-1, Kitagun, Kagawa 761-0793, Japan. kusaka@kms.ac.jp
authors: Takashi
authors: T
authors: Kusaka
authors: Satoshi
authors: S
authors: Matsuura
authors: Yuka
authors: Y
authors: Fujikawa
authors: Kensuke
authors: K
authors: Okubo
authors: Kou
authors: K
authors: Kawada
authors: Masanori
authors: M
authors: Namba
authors: Hitoshi
authors: H
authors: Okada
authors: Tadashi
authors: T
authors: Imai
authors: Kenichi
authors: K
authors: Isobe
authors: Susumu
authors: S
authors: Itoh
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000378:metabolism*; D004734:Energy Metabolism / Q000502:physiology*; D045604:Extracellular Fluid / Q000378:metabolism; D020925:Hypoxia-Ischemia, Brain / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D010710:Phosphates / Q000378:metabolism; D010725:Phosphocreatine / Q000378:metabolism; D010759:Phosphorus Isotopes; D010766:Phosphorylation; D013552:Swine
chemical_list: D000596:Amino Acids; D010710:Phosphates; D010759:Phosphorus Isotopes; D010725:Phosphocreatine