Open AccessThe effects of carbamazepine in the intrahippocampal kainate model of temporal lobe epilepsy depend on seizure definition and mouse strain
Author(s) -
Twele Friederike,
Töllner Kathrin,
Bankstahl Marion,
Löscher Wolfgang
Publication year - 2016
Publication title -
epilepsia open
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.247
H-Index - 16
ISSN - 2470-9239
DOI - 10.1002/epi4.2
Subject(s) - carbamazepine , epilepsy , kainate receptor , electroencephalography , kindling model , phenobarbital , hippocampal sclerosis , anesthesia , anticonvulsant , temporal lobe , medicine , hippocampal formation , hippocampus , kainic acid , neuroscience , psychology , pharmacology , glutamate receptor , receptor , ampa receptor
Summary Objective Mesial temporal lobe epilepsy ( TLE ) with hippocampal sclerosis is a predominant form of acquired epilepsy, characterized by recurrent simple and complex partial seizures that are often resistant to treatment. Mice developing spontaneous recurrent nonconvulsive and convulsive seizures after intrahippocampal injection of the excitotoxic glutamate agonist kainate are thought to represent a valuable model of mesial TLE . Epileptic electroencephalogram (EEG) activity recorded in this model from the kainate focus in the ipsilateral hippocampus is resistant to antiseizure drugs such as carbamazepine ( CBZ ). We compared the efficacy of CBZ in this model in two different mouse strains ( FVB /N and NMRI ). Furthermore, we evaluated whether changes in the definition of electrographic seizures affect the antiseizure efficacy of CBZ . Methods As in previous studies, two types of epileptic EEG activity were defined: high‐voltage sharp waves ( HVSW s) and hippocampal paroxysmal discharges ( HPD s). The characteristics of these paroxysmal EEG events in epileptic mice were compared with EEG criteria for nonconvulsive seizures in patients. For HVSW s, different spike frequencies, interevent intervals, and amplitudes were used as inclusion and exclusion criteria. In addition to CBZ , some experiments were performed with diazepam ( DZP ) and phenobarbital ( PB ). Results Female epileptic FVB /N mice predominantly exhibited frequent HVSW s, but only infrequent HPD s or secondarily generalized convulsive seizures. Slight changes in HVSW definition determined whether they were resistant or responsive to CBZ . Male NMRI mice exhibited both HVSW s and HPD s. HVSW s were more resistant than HPD s to suppression by CBZ . Both types of epileptic EEG activity were rapidly suppressed by DZP and PB . Significance The data demonstrate that focal electrographic seizures in the intrahippocampal kainate mouse model are less resistant than previously thought. Both mouse strain and the criteria chosen for definition of EEG seizures determine whether such seizures are drug‐resistant or ‐responsive.