title: The temporal profile of cerebral blood flow and tissue metabolites indicates sustained metabolic depression after experimental subarachnoid hemorrhage in rats.
abstract: BACKGROUND
  Derangement of cerebral metabolism occurs after various insults such as ischemia, traumatic brain injury, and subarachnoid hemorrhage (SAH).
  
  
  OBJECTIVE
  To investigate the course of cerebral blood flow and metabolic parameters in the first hours after experimental SAH.
  
  
  METHODS
  Sixteen Sprague-Dawley rats were subjected to SAH using the endovascular filament model or served as controls (8 rats in each group). Local cerebral blood flow and intracranial pressure were measured continuously. Microdialysis samples were acquired in 30-minute intervals for 6 hours after SAH. Concentrations of glucose, lactate, pyruvate, and glutamate were determined.
  
  
  RESULTS
  After induction of SAH, cerebral perfusion pressure and local cerebral blood flow sharply decreased. The decrease in local cerebral blood flow exceeded the decrease in cerebral perfusion pressure throughout the observation period. Glutamate concentrations in microdialysis samples increased sixfold and recovered to baseline levels. Lactate concentrations immediately increased after SAH, recovered incompletely, and remained above the levels of control animals until the end of the sampling period. Pyruvate concentrations showed a delayed increase starting 2 hours after SAH.
  
  
  CONCLUSIONS
  The course of cerebral blood flow after SAH resembles global ischemia followed by a continuous low-flow state caused by a sudden decrease in cerebral perfusion pressure and acute vasoconstriction. The courses of lactate and pyruvate concentrations indicate a persistently deranged aerobic metabolism.
authors.affiliation: Department of Neurosurgery, University of Würzburg, Würzburg, Germany. Westermaier.T@nch.uni-wuerzburg.de
authors.forename: Thomas
authors.initials: T
authors.lastname: Westermaier
authors.forename: Alina
authors.initials: A
authors.lastname: Jauss
authors.forename: Jörg
authors.initials: J
authors.lastname: Eriskat
authors.forename: Ekkehard
authors.initials: E
authors.lastname: Kunze
authors.forename: Klaus
authors.initials: K
authors.lastname: Roosen
mesh_terms: D000818:Animals; D001921:Brain / Q000098:blood supply / Q000378:metabolism* / Q000503:physiopathology*; D001923:Brain Chemistry / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D017551:Microdialysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013345:Subarachnoid Hemorrhage / Q000378:metabolism* / Q000503:physiopathology*; D013995:Time