Nonconvulsive status epilepticus in rats: Impaired responsiveness to exteroceptive stimuli

An animal model of human complex partial status epilepticus induced by lith ium chloride and pilocarpine administration was developed in our laboratory . The objective of the study was to provide a detailed analysis of both ict al and postictal behavior and to quantify seizure-related morphological dam age, In order to determine the animal's responsiveness to either visual or olfactory stimuli, adult male rats were submitted to the following behavior al paradigms: the object response test, the social interaction test, and th e elevated plus-maze test. The rotorod test was used to evaluate motor perf ormance, Two weeks after status epilepticus, brains were morphologically ex amined and quantification of the brain damage was performed. Profound impai rment of behavior as well as responsiveness to exteroceptive stimuli;correl ated with the occurrence of epileptic EEG activity. When the epileptic EEG activity ceased, responsiveness of the pilocarpine-treated animals was rene wed. However, remarkable morphological damage persisted in the cortical reg ions two weeks later. This experimental study provides support for the clin ical evidence that even nonconvulsive epileptic activity may cause brain da mage. We suggest that the model can be used for the study of both functiona l and morphological consequences of prolonged nonconvulsive seizures. (C) 2 000 Elsevier Science B.V. All rights reserved.