OBJECTIVE: To study the effects of extracellular bromide in a novel immature rat pilocarpine model compared to the standard adolescent rat model. METHODS: We employed an immature rat model of repetitive pilocarpine-induced status epilepticus (340 mg/kg on postnatal days 9, 11 and 15). The electrophysiological characterization of the Schaffer collateral CA1-synapse and of CA1 pyramidal neurons was performed in 30-70 day-old animals. To explore the effects of bromide, 20 mM NaCl in the bath solution was replaced by 20 mM NaBr. We compared our findings in the immature model with data from the standard adolescent model of a single pilocarpine-induced status epilepticus (340 mg/kg on postnatal day 30) obtained from 40-90 day-old animals. RESULTS: In the immature, but not in the adolescent model, extracellular bromide (20 mM) enhanced the GABA SIGNIFICANCE: The immature model, but not the commonly used adolescent pilocarpine model, showed a persistent bromide-enhanced GABA