Prenatal morphine exposure differentially alters seizure susceptibility indeveloping female rats

We examined the effect of prenatal morphine exposure (5-10 mg/kg on days 11 -18 of gestation) on seizure susceptibility in female rats during developme nt. The effect of morphine exposure on flurothyl-induced seizures was age-d ependent. At postnatal day (PN) 15, morphine exposure decreased both clonic and tonic-clonic seizure thresholds compare to saline controls. At PN 25, morphine exposure did not alter the clonic seizure threshold but increased the threshold to tonic-clonic seizure. At PN 38, morphine exposure did not influence either threshold. The data suggest that the effects of prenatal e xposure to opioids on seizures are age-related and transient. (C) 1999 Else vier Science B.V. All rights reserved.