title: [Effects of cPKCβII/γ membrane translocation ischemic/hypoxic tolerance induced by morphine postconditioning in hippocampal slices].
abstract: OBJECTIVE
  To determine whether or not morphine postconditioning can induce ischemic/hypoxic tolerance in neurons subjected to reperfusion injury after oxygen-glucose deprivation (OGD).
  
  
  METHODS
  Hippocampal slices of 400 µm thickness were prepared from healthy adult male BALB/c mice. The slices were incubated in oxygen-saturated ACSF without or with calcium, then were subjected to OGD for 20 min. After recovery, the samples were immersed in oxygenated artificial fluid for 2 hours in the presence or absence of morphine postconditioning at 3 µmol/L during the first 5 - 60 min. The assessment of slices injury was performed by a determination of the intensity of slice stain incubated with TTC (2% 2, 3, 5-triphenyltetrazolium chloride) and the leakage rate of LDH also evaluated. At the designated periods during incubation, some slices were immersed into liquid nitrogen for a later analysis of Western blot. The frozen slices were homogenized, sonicated and centrifuged to separate soluble and particulate proteins. 10% SDS-PAGE Western blot was used to identify the changes of membrane-specific translocation of cPKCβII/γ.
  
  
  RESULTS
  After reperfusion, the cell survival significantly decreased with the elongation of OGD (51.4%). The release rate of LDH (184.05%) significantly increased simultaneously. In hippocampal slices postconditioned with morphine for 20 - 60 min, the release rate of LDH (136%, 142%, 144%) significantly decreased as compared with the group OGD. In the hippocampal slices postconditioned with morphine for 10 - 30 min, the cell survival rate (64.9%, 69.9%, 63.5%) significantly increased as compared with reperfusion alone. cPKCγ of particulate fraction increased versus the control. And there was a corresponding decrease of cytosolic fraction. Morphine postconditioning significantly inhibited the cPKCγ isoform-specific membrane translocation. It declined from 136% in the group OGD to 123%, 118%, 114% in the group morphine 20 - 60 min. cPKCβII membrane translocation had no change.
  
  
  CONCLUSIONS
  Morphine postconditioning can induce ischemic tolerance in nerons. The protective mechanism may be through inhibiting the cPKCγ isoform-specific membrane translocation.
authors.affiliation: Department of Anesthesiology, Capital Medical University, Beijing, China.
authors.forename: Hai-li
authors.initials: HL
authors.lastname: Hu
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.forename: Fang
authors.initials: F
authors.lastname: Ji
authors.forename: Tian-zuo
authors.initials: TZ
authors.lastname: Li
authors.forename: Jun-fa
authors.initials: JF
authors.lastname: Li
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D005947:Glucose / Q000378:metabolism; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009020:Morphine / Q000494:pharmacology*; D018696:Neuroprotective Agents / Q000494:pharmacology; D010100:Oxygen / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism*; D064546:Protein Kinase C beta; D015427:Reperfusion Injury / Q000378:metabolism / Q000517:prevention & control*
chemical_list: D018696:Neuroprotective Agents; D009020:Morphine; D011493:Protein Kinase C; D064546:Protein Kinase C beta; D005947:Glucose; D010100:Oxygen