Effects of Acute Perinatal Asphyxia in the Rat Hippocampus

In the present work, we have used a rat animal model to study the early effects of intrauterine asphyxia occurring no later than 60 min following the cesarean-delivery procedure. Transitory hypertonia accompanied by altered posture was observed in asphyxiated pups, which also showed appreciably increased lactate values in plasma and hippocampal tissues. Despite this, there was no difference in terms of either cell viability or metabolic activities such as oxidation of lactate, glucose, and glycine in the hippocampus of those fetuses submitted to perinatal asphyxia with respect to normoxic animals. Moreover, a significant decrease in glutamate, but not GABA uptake was observed in the hippocampus of asphyctic pups. Since intense ATP signaling especially through P2X₇ purinergic receptors can lead to excitotoxicity, a feature which initiates neurotransmission failure in experimental paradigms relevant to ischemia, here we assessed the expression level of the P2X₇ receptor in the paradigm of perinatal asphyxia. A three-fold increase in P2X₇ protein was transiently observed in hippocampus immediately following asphyxia. Nevertheless, further studies are needed to delineate whether the P2X₇ receptor subtype is involved in the pathogenesis, contributing to ongoing brain injury after intrapartum asphyxia. In that case, new pharmacologic intervention strategies providing neuroprotection during the reperfusion phase of injury might be identified.