Abstract
SUMMARY OF COMMUNICATIONS CELL DAMAGE AND NEUROGENESIS IN THEDENTATE GRANULE CELL LAYER OF ADULT RATSAFTER PILOCARPINE- OR KAINATE-INDUCEDSTATUS EPILEPTICUS CovolanL.,RibeiroL.T.C.,LongoB.M.andMelloL.E.A.M. Department of Physiology, UNIFESP, 04023-900 Sao Paulo,SP.Presented by A.C.M.Paiva Dentate granule cells are generally considered to berelatively resistant to excitotoxicity and have been asso-ciated to robust synaptogenesis after neuronal damage.Synaptic reorganization of dentate granule cell axons,the mossy fibers, has been suggested to be relevant forhyperexcitability in human temporal lobe epilepsy andanimal models. A recent hypothesis has suggested thatmossy fiber sprouting is dependent on newly formed den-tate granule cells. However, we have recently demon-strated that cycloheximide (CHX) can block the mossyfiber sprouting that would be otherwise induced by dif-ferent epileptogenic agents and do not interfere withepileptogenesis in those models. Here, we investigatedcell damage and neurogenesis in the dentate gyrus ofpilocarpine- or kainate-treated animals with or withoutthe co-administration of CHX. Dentate granule cells werehighly vulnerable to pilocarpine induced-status epilep-ticus (SE), but hardly damaged by kainate induced-SE.CHX-pretreatment markedly reduced the number of in-jured neurons after pilocarpine-induced SE. Induction ofSE dramatically increased the mitotic rate of KA and KA+ CHX treated animals. Induction of SE in animals in-jected with pilocarpine alone led to increases of betweentwo to sevenfold in the mitotic rate of dentate granulecells as compared to increases of between five and thirty-fold for pilocarpine+CHX animals. These observationsindicate that in presence of cycloheximide the increase ofthe mitotic rate after pilocarpine-induced SE may be duetoprotectionofavulnerableprecursorcellpopulationthatwould otherwise degenerate. We further suggest that themossy fiber sprouting and neurogenesis of granule cellsare not necessarily related events. — ( September 14,1999 ).
Highlights
Dentate granule cells are generally considered to be relatively resistant to excitotoxicity and have been associated to robust synaptogenesis after neuronal damage
We have recently demonstrated that cycloheximide (CHX) can block the mossy fiber sprouting that would be otherwise induced by different epileptogenic agents and do not interfere with epileptogenesis in those models
Induction of status epilepticus (SE) in animals injected with pilocarpine alone led to increases of between two to sevenfold in the mitotic rate of dentate granule cells as compared to increases of between five and thirtyfold for pilocarpine+CHX animals
Summary
Ramirez3, Nobuko Yoshida1, José Franco da Silveira1 1Departamento de Micro, Imuno e Parasitologia, Escola Paulista de Medicina, UNIFESP, 04023-062 São Paulo, Brasil; 2Unidad de Parasitologia, Universidad de Antofagasta, Antofagasta, Chile; 3Instituto de Biologia Experimental, Universidad Central de Venezuela, Aptado 47525, Caracas 1041-A, Venezuela Presented by Luiz R. Gp90 and gp82 are present in multiple copies, distributed in several chromosomes, and this gene family can be divided into subsets on the basis of hybridization patterns obtained with probes derived from different regions of gp90 and gp82 genes (Araya et al 1994); [Cano et al 1995.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
