Behavioral, Morphologic, and Electroencephalographic Evaluation of Seizures Induced by Intrahippocampal Microinjection of Pilocarpine

Authors

  • Marcio De A. Furtado,

    1. Neurophysiology and Experimental Neuroethology Laboratory, Physiology Department, Ribeirão Preto School of Medicine, Ribeirão Preto, São Paulo, Brazil
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  • Glaucia K. Braga,

    1. Neurophysiology and Experimental Neuroethology Laboratory, Physiology Department, Ribeirão Preto School of Medicine, Ribeirão Preto, São Paulo, Brazil
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  • José A. C. Oliveira,

    1. Neurophysiology and Experimental Neuroethology Laboratory, Physiology Department, Ribeirão Preto School of Medicine, Ribeirão Preto, São Paulo, Brazil
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  • Flavio Del Vecchio,

    1. Neurophysiology and Experimental Neuroethology Laboratory, Physiology Department, Ribeirão Preto School of Medicine, Ribeirão Preto, São Paulo, Brazil
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  • Norberto Garcia-Cairasco

    1. Neurophysiology and Experimental Neuroethology Laboratory, Physiology Department, Ribeirão Preto School of Medicine, Ribeirão Preto, São Paulo, Brazil
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Address correspondence and reprint requests to Dr. N. Garcia-Cairasco at Neurophysiology and Experimental Neuroethology Laboratory, Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, 14049-900, Ribeirão Preto, SP, Brazil. E-mail: ngcairas@fmrp.usp.br

Abstract

Summary:  Purpose: We studied, by means of video-EEG and neo-Timm histochemistry, the behavioral, electrophysiologic, and structural characteristics of seizures induced by intrahippocampal microinjection of pilocarpine (HIP-PILO), a selective model of temporal lobe epilepsy (TLE).

Methods: We investigated the behavioral and electrophysiologic (hippocampus and amygdala EEG) evaluation of status epilepticus (SE) induced by HIP-PILO and the consequent spontaneous recurrent seizures (SRSs). We evaluated hippocampal structural rearrangements after SE by means of neo-Timm staining.

Results: HIP-PILO induced SE in 17 (71%) of 24 animals. Although three animals displayed spontaneous remission of SE (not used in analysis) before the established SE duration (90 min), none of those undergoing SE died. Of SE animals, 10 (71%) of 14 had SRSs. All animals with SE had clear-cut mossy fiber sprouting (MFS) in the inner molecular layer of the dentate gyrus and epileptiform activity in hippocampus and amygdala.

Conclusions: HIP-PILO rats displayed SE, SRS, MFS, and limbic epileptiform activity, without animal loss after SE. Thus, our data support this as a selective and efficient model of TLE.

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