title: Neuroprotective efficacy of intra-arterial and intravenous magnesium sulfate in a rat model of transient focal cerebral ischemia.
abstract: BACKGROUND
  Many neurovascular procedures necessitate temporary occlusion of cerebral arteries. In this situation neuroprotective drugs may increase the safety of the procedures. Magnesium may inhibit ischemic damage by anti-excitotoxic, calcium channel blocking and vasodilatory action. Some evidence suggests that intra-arterial administration might provide a much higher degree of protection than intravenous treatment. In this study the neuroprotective efficacy of intra-arterial and intravenous magnesium administration was examined in a rat model of transient focal ischemia.
  
  
  METHODS
  34 male Sprague-Dawley rats were subjected to 90 minutes of middle cerebral artery occlusion (MCAO) by an intraluminal thread. Before ischemia, animals received an infusion of either (1) vehicle (0.9% NaCl) (2) MgSO4 intra-arterially or (3) MgSO4 intravenously. Local cortical blood flow (LCBF) was continuously measured by laser-Doppler flowmetry. Functional deficits were quantified daily, infarct volumes were assessed histologically after 7 days.
  
  
  RESULTS
  There was no difference between the treatment groups concerning LCBF. Magnesium serum levels increased from approximately 1 mmol/l to approximately 1.8 mmol/l by either route of administration. Both intra-arterial and intravenous treatment improved neurological recovery and equally reduced total infarct volume by approximately 25%.
  
  
  CONCLUSIONS
  The results indicate that there is no advantage of intra-arterial over intravenous magnesium administration. A comparison with previous studies suggests that even within the normal range of serum magnesium concentrations, low-normal levels may be hazardous and high-normal levels may be protective in transient focal ischemia.
authors.affiliation: Department of Neurosurgery, Klinikum Grosshadern, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Th
authors.initials: T
authors.lastname: Westermaier
authors.forename: E
authors.initials: E
authors.lastname: Hungerhuber
authors.forename: St
authors.initials: S
authors.lastname: Zausinger
authors.forename: A
authors.initials: A
authors.lastname: Baethmann
authors.forename: R
authors.initials: R
authors.lastname: Schmid-Elsaesser
mesh_terms: D000818:Animals; D002544:Cerebral Infarction / Q000473:pathology; D002560:Cerebrovascular Circulation; D007269:Injections, Intra-Arterial; D007275:Injections, Intravenous; D002546:Ischemic Attack, Transient / Q000188:drug therapy* / Q000503:physiopathology; D017078:Laser-Doppler Flowmetry; D008278:Magnesium Sulfate / Q000008:administration & dosage*; D008297:Male; D018696:Neuroprotective Agents / Q000008:administration & dosage*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D018696:Neuroprotective Agents; D008278:Magnesium Sulfate