Magnetic Resonance Spectroscopy Studies on Changes in Cerebral Calcium and Zinc and the Energy State Caused by Excitotoxic Amino Acids

• Autor: Thatcher, N. M. ; Prior, M. J. W. ; Morris, P. G. ; Bachelard, H. S.
• Assuntos: amino acids (excitatory) ; Animals ; Biological and medical sciences ; Calcium ; Calcium - metabolism ; Central nervous system ; Central neurotransmission. Neuromudulation. Pathways and receptors ; Cerebral cortex ; Cerebral Cortex - drug effects ; Cerebral Cortex - metabolism ; Cerebral Cortex - physiology ; Dizocilpine Maleate - pharmacology ; Energy Metabolism - drug effects ; Energy state ; Excitotoxicity ; Fundamental and applied biological sciences. Psychology ; Glutamic Acid - pharmacology ; Guinea Pigs ; Hippocampus ; Hippocampus - drug effects ; Hippocampus - metabolism ; Hippocampus - physiology ; In Vitro Techniques ; Magnetic Resonance Spectroscopy ; Membrane Potentials - drug effects ; Membrane Potentials - physiology ; Mice ; MK‐801 ; Neurotoxins - pharmacology ; Phosphocreatine - metabolism ; Vertebrates: nervous system and sense organs ; Zinc ; Zinc - metabolism
• É parte de: Journal of neurochemistry, 1999-06, Vol.72 (6), p.2471-2478
• Notas: The present address of Dr. N. M. Thatcher is Pfizer Central Research, Discovery Biology Department, Sandwich, Kent CT13 9NJ, U.K.
  tetraacetic acid; MK‐801, (+)‐5‐methyl‐10,11‐dihydro‐5
  and [Zn
  cyclohepten‐5,10‐imine maleate; MRS, magnetic resonance spectroscopy; PCr, phosphocreatine.
  H
  i
  Lippincott Williams & Wilkins, Inc., Philadelphia
  dibenzo
  o
  free intracellular calcium and zinc concentration, respectively; 5FBAPTA, 5,5′‐difluoro‐1,2‐bis
  N,N,N′,N
  a,d
  2+
  aminophenoxy)ethane
  ]
  Ca
  Abbreviations used
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  SourceType-Scholarly Journals-1
  ObjectType-Feature-1
  content type line 23
  
• Descrição: : Under control conditions, superfused hippocampal slices exhibited a significantly higher phosphocreatine (PCr)/ATP ratio than cortical slices; the evidence suggests that this is due to lower concentrations of ATP, rather than higher concentrations of PCr. Glutamate caused relatively rapid decreases in PCr and ATP levels to ∼45%, accompanied or immediately followed by an increased free intracellular calcium concentration ([Ca2+]i) and the release of Zn2+ in the cortex. In the hippocampus PCr and ATP decreased further to ∼20% of control values, but the changes in [Ca2+]i and Zn2+ content were slower. This is in contrast to the effects of depolarisation, which produced the same rapid changes in the energy state and [Ca2+]i, with no detectable Zn2+, in both tissues. NMDA causes effects similar to those of glutamate in the cortex (decreases in the energy state, increased [Ca2+]i, and release of Zn2+). Pretreatment of the cortex for 1 h with the NMDA blocker MK‐801 prevented all of the observed effects of NMDA. In contrast, pretreatment with MK‐801 had no detectable effect on the increase in [Ca2+]i or the decreases in PCr and ATP caused by glutamate, although it prevented the release of zinc. The results are discussed in relation to the function of the NMDA subtype of glutamate receptor in excitotoxicity.
  
• Editor: Oxford UK: Blackwell Science Ltd
  
• Idioma: Inglês