Protein S100B release from rat brain slices during and after ischemia: comparison with lactate dehydrogenase leakage.
One hour of ischemia significantly increased protein S100B release from rat brain slices without altering lactate dehydrogenase leakage. Reoxygenation of the ischemic slices, however, increased the levels of these biochemical markers in the medium. Although removal of extracellular Ca(+2) ions from the medium did not alter the basal lactate dehydrogenase leakage from cortical slices, an excessive increase in basal protein S100B release was seen under this condition. Ischemia and/or reoxygenation induced enhancements in these markers were attenuated by removal of Ca(+2) ions from the medium. Ischemia significantly increased glutamate release, but neither ischemia nor reoxygenation induced rises in protein S100B and lactate dehydrogenase levels were altered by glutamate receptor antagonists. Rising the glutamate levels in the medium by each ouabain or exogenous glutamate, moreover, failed in exerting an ischemia like effect on protein S100B and LDH outputs. In contrast, exogenous glutamate added into the medium protected the slices against reoxygenation induced increments in protein S100B and lactate dehydrogenase levels. These results indicate that protein S100B has a greater sensitivity against ischemia than lactate dehydrogenase in in vitro brain slice preparations. Since neither exogenous glutamate nor enhancements of the extracellular glutamate levels by ouabain had an ischemia like effect, and since glutamate receptor antagonists were also unsuccessful, it seems unlikely that ischemia-induced increase in glutamate release is directly involved in protein S100B release or lactate dehydrogenase leakage determined in the present study.
Büyükuysal
Rifat Levent
RL
Uludağ University, Medical School, Department of Pharmacology and Clinical Pharmacology, 16059 Bursa, Turkey. lrbuyuk@uludag.edu.tr
D000818:Animals; D001921:Brain / Q000378:metabolism* / Q000503:physiopathology; D002545:Brain Ischemia / Q000378:metabolism* / Q000503:physiopathology; D002118:Calcium / Q000378:metabolism; D004195:Disease Models, Animal; D004734:Energy Metabolism / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D018698:Glutamic Acid / Q000187:drug effects / Q000378:metabolism*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism*; D008297:Male; D009414:Nerve Growth Factors / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D009924:Organ Culture Techniques; D010042:Ouabain / Q000494:pharmacology; D010100:Oxygen / Q000378:metabolism / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017470:Receptors, Glutamate / Q000187:drug effects / Q000378:metabolism; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology
D004791:Enzyme Inhibitors; D018691:Excitatory Amino Acid Antagonists; D009414:Nerve Growth Factors; D017470:Receptors, Glutamate; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; C579158:S100b protein, rat; D018698:Glutamic Acid; D010042:Ouabain; D007770:L-Lactate Dehydrogenase; D010100:Oxygen; D002118:Calcium