HYPOXIC-ISCHEMIC ENCEPHALOPATHY SUSTAINED IN EARLY POSTNATAL LIFE MAYRESULT IN PERMANENT EPILEPTIC ACTIVITY AND AN ALTERED CORTICAL CONVULSIVE THRESHOLD IN RAT

The aim of this study was to investigate whether the rat cerebral cort ex, damaged by hypoxia-ischemia in early postnatal life, would show an increased seizure susceptibility and/or spontaneous epileptic dischar ges in adulthood. To that end 12-13-day-old Wistar rat pups were unila terally exposed to hypoxic-ischemic conditions. After a recovery perio d of about 2.5 months, recording and stimulation electrodes were perma nently implanted over the left and right fronto-parietal neocortex. Lo ng-term recording of baseline electrocortical activity showed that onl y those animals that had incurred severe brain damage, as was reflecte d by the presence of a cortical infarction, ran a high risk of develop ing permanent epileptic activity. With the aid of the stimulation elec trodes the initial threshold for localized seizure activity was found to be the same for the experimental and non-treated groups. However, w hen the kindling-like decline of this threshold was assessed by repeat ed testing over a 2-week period, the infarcted animals tended to a mor e rapid decline but a higher stabilization level than the non-infarcte d and control animals.