DECREASE OF BRAIN PROTEIN-KINASE-C, PROTEIN-KINASE-A, AND CYCLIN-DEPENDENT KINASE CORRELATING WITH PH PRECEDES NEURONAL DEATH IN NEONATAL ASPHYXIA

Background: Acidosis, energy depletion, overstimulation by excitatory amino acids, and free radical-mediated reactions are the major, curren t concepts for the explanation of damage and death resulting from asph yxia, Impaired protein phosphorylation by protein kinase C represents another mechanism incriminated in cell death. Methods: We used a nonso phisticated perinatal asphyxia model to study brain (frontal cortex) p H, ATP, protein kinases PKC, PKA, and cyclin-dependent kinase, We used o-tyrosine, a marker for hydroxyl radical attack, and LPO 586, a spec trophotometric assay, to study lipid peroxidation products, The antiox idant enzymes catalase, superoxide dismutase, and glutathione peroxida se were used in the frontal cortex. In addition, a cell death ELISA an d histology to evaluate cell death were performed, Results: Brain pH a nd protein kinases were decreasing with the length of the asphyctic pe riods, and energy depletion was shown by a drop of ATP levels, whereas no evidence for the involvement of free radical-mediated mechanisms w as obtained, Cell death was shown by the cell death ELISA as early as 10 minutes after the asphyctic period, and histologically, cell death could be revealed but not before day 8 after asphyxia, Conclusion: Aci dosis and/or impaired protein kinases, but not free radical mechanisms , may play a role In the pathobiochemistry of cell death in neonatal a sphyxia of the rat.