Evidence for increased seizure susceptibility in rats exposed to cocaine in utero

Clinical observations indicate that cocaine use during pregnancy is a major health concern in the United States and may result in seizure-like behavior in the offspring. In the present study, we investigated whether prenatal cocaine exposure altered seizure thresholds measured in Sprague-Dawley rats, 60-90 days postnatal. In vitro postnatal studies, focusing on hippocampal tissue, revealed a reduced threshold for both electrical stimulation-and potassium-induced epileptiform discharges in slices from cocaine-exposed animals. Modest elevation of extracellular potassium concentration from 3 to 6 mM KCl elicited spontaneous epileptiform discharges in the majority of slices from cocaine-exposed animals (13/20) but rarely in slices from saline-exposed animals (2/18). In vivo studies on awake, freely behaving adult rats indicated a significant reduction in thresholds for both flurothyl-and kainic acid-induced seizures in cocaine-exposed animals. Video-EEG monitoring during administration of kainic acid revealed reduced latencies to first 'electrographic seizure' and first 'electrographic seizure with behavior' in rats exposed to cocaine in utero compared to saline-treated controls. These studies provide strong experimental evidence that adult animals exposed to cocaine during gestation are at high risk for the development of seizure activity. (C) 1997 Elsevier Science B.V.