title: Effects of preconditioning with normobaric hyperoxia on Na⁺/Ca²⁺ exchanger in the rat brain.
abstract: BACKGROUND
  Recent studies suggest that normobaric hyperoxia (HO) reduces hypoxia-reoxygenation injury in the rat brain. We have attempted to determine the effect of HO on Na(+)-Ca(2+) exchangers (NCX) in the rat stroke model.
  
  
  METHODS
  Rats were divided into two experimental groups. The first group was exposed to 95% inspired HO for 4h/day for 6 consecutive days (HO). The second group acted as the control, and was exposed to 21% oxygen in the same chamber. Each main group was subdivided to middle cerebral artery occlusion (MCAO-operated) and intact (without any surgery) subgroups. After 48 h from pretreatment, MCAO-operated subgroups were subjected to 60 min of right MCAO. After 24h reperfusion, neurologic deficit score (NDS) and infarct volume were measured in MCAO-operated subgroups. The NCXs expression levels of the core, penumbra and subcortical regions were assessed in sham-operated and intact subgroups.
  
  
  RESULTS
  Preconditioning with HO decreased NDS and infarct volume, and increased the expression of NCX1, NCX2 and NCX3 in the penumbra, NCX2, NCX3 in the core and NCX1 and NCX3 in the subcortex.
  
  
  CONCLUSIONS
  Although further studies are needed to clarify the mechanisms of ischemic tolerance, HO partly is associated with the expression of NCX1, 2, 3 consistent with an active role in the genesis of ischemic protection.
authors: Department of Physiology, Faculty of Biological Sciences, Shahid Beheshti University, GC, Tehran, Iran.
authors: E
authors: E
authors: Mohammadi
authors: M R
authors: MR
authors: Bigdeli
mesh_terms: D000818:Animals; D001921:Brain / Q000098:blood supply / Q000378:metabolism* / Q000473:pathology; D020520:Brain Infarction / Q000209:etiology / Q000517:prevention & control; D004195:Disease Models, Animal; D005786:Gene Expression Regulation / Q000502:physiology; D018496:Hyperoxia; D020244:Infarction, Middle Cerebral Artery / Q000150:complications / Q000473:pathology*; D019194:Ischemic Preconditioning / Q000379:methods*; D017078:Laser-Doppler Flowmetry; D008297:Male; D009460:Neurologic Examination; D018696:Neuroprotective Agents / Q000627:therapeutic use*; D010100:Oxygen / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D019831:Sodium-Calcium Exchanger / Q000235:genetics / Q000378:metabolism*
chemical_list: D018696:Neuroprotective Agents; C110927:Slc8a2 protein, rat; C491101:Slc8a3 protein, mouse; D019831:Sodium-Calcium Exchanger; C110374:sodium-calcium exchanger 1; D010100:Oxygen