title: Nuclear-envelope nucleoside triphosphatase kinetics and mRNA transport following brain ischemia and reperfusion.
abstract: OBJECTIVE
  We attempted to determine whether the reduced egress of mRNA from brain nuclei following in vivo ischemia and reperfusion is caused by direct damage to the nuclear pore-associated NTPase that impairs the system for nuclear export of polyadenylated, or poly(A)+, mRNA.
  
  
  METHODS
  Prospective animal study.
  
  
  METHODS
  NTPase activity and poly(A)+ mRNA transport were studied in nuclear envelope vesicles (NEVs) prepared from canine parietal cortex isolated after 20 minutes of ischemia or 20 minutes of ischemia and 2 or 6 hours of reperfusion.
  
  
  RESULTS
  Brain NEV NTPase Michaelis-Menten constant (Km) and maximum uptake velocity (Vmax) and the ATP-stimulated poly(A)+ mRNA egress rates were not significantly affected by ischemia and reperfusion. In vitro exposure of the NEVs to the OH. radical-generating system completely abolished NTPase activity.
  
  
  CONCLUSIONS
  We conclude that brain ischemia and reperfusion do not induce direct inhibition of nucleocytoplasmic transport of poly(A)+ mRNA. This suggests that the nuclear membrane is not exposed to significant concentrations of OH. radical during reperfusion.
authors.affiliation: Department of Emergency Medicine, Wayne State University, Detroit, Michigan, USA.
authors.forename: B R
authors.initials: BR
authors.lastname: Tiffany
authors.forename: B C
authors.initials: BC
authors.lastname: White
authors.forename: G S
authors.initials: GS
authors.lastname: Krause
mesh_terms: D017766:Acid Anhydride Hydrolases / Q000493:pharmacokinetics*; D000818:Animals; D001692:Biological Transport; D002545:Brain Ischemia / Q000378:metabolism*; D004285:Dogs; D006323:Heart Arrest / Q000378:metabolism; D017665:Hydroxyl Radical / Q000378:metabolism; D009685:Nuclear Envelope / Q000378:metabolism; D043583:Nucleoside-Triphosphatase; D011446:Prospective Studies; D012333:RNA, Messenger / Q000378:metabolism*; D015424:Reperfusion
chemical_list: D012333:RNA, Messenger; D017665:Hydroxyl Radical; D017766:Acid Anhydride Hydrolases; D043583:Nucleoside-Triphosphatase