UNCORRECTED PROOF Epilepsy Research xxx (2003) xxx–xxx Levels of the synaptic protein X11 alpha/mint1 are 3 increased in hippocampus of rats with epilepsy 4 Carla Alessandra Scorza a , Yaima del Carmem Garrido a , Ricardo Mario Arida a , Debora Amado a , Esper Abrão Cavalheiro a , Maria da Graça Naffah-Mazzacoratti b,∗ 5 6 a Laboratório de Neurociˆ encia, Disciplina de Neurologia Experimental, Universidade Federal de São Paulo, 7 Rua Botucatu 862, Ed. Leal Prado CEP-04023-900, São Paulo, Brazil 8 b Disciplina de Bioqu´ ımica, Universidade Federal de São Paulo, Rua Botucatu 862, Ed. Leal Prado CEP-04023-900 São Paulo, Brazil 9 Received 8 March 2003; received in revised form 9 September 2003; accepted 8 October 2003 10 Abstract 11 X11 alpha or Mint1 is a protein containing an N-terminal sequence, which binds to Munc-18 protein, a middle phosphotyrosine- binding domain (PTB) and two C-terminal PDZ (Post-synaptic density/Discs large/Zone Occludens-1) domains. The PDZ do- mains, which mediate protein–protein interactions have been shown to be involved in the organization of synaptic signaling pathways. Mint1 plays an important role in vesicle synaptic transport toward the active zone at the pre-synaptic site, and also participates in the transport of NR2B subunit of the NMDA receptor, to the post-synaptic site. To investigate the participation and distribution of this protein in the hippocampal subfield of rats submitted to the pilocarpine model of epilepsy, Mint1 was analyzed using Western blotting and immunohistochemistry. Animals of 5 h of status epilepticus showed decreased levels of this protein in the hippocampus when compared to the control animals. In contrast, animals from seizure-free period (silent group) and during spontaneous seizures phase (chronic group) showed increased Mint1 immunostaining in all hippocampal subfields, mainly in the dentate gyrus, when compared to the control group. The blotting confirmed the results obtained by immunohistochemistry. The present work suggests that Mint1 may be related to hippocampal plasticity during epileptogenesis in the pilocarpine model of temporal lobe epilepsy. 12 13 14 15 16 17 18 19 20 21 22 23 © 2003 Published by Elsevier B.V. 24 Keywords: Mint1; Epilepsy; Pilocarpine; Excitatory synapses 27 1. Introduction 29 Synaptic junctions are highly specialized structures 30 designed to promote a rapid and efficient transmission 31 ∗ Corresponding author. Tel.: +55-11-576-4509; fax: +55-11-549-4793. E-mail address: naffahmazz.nexp@epm.br (M.d.G. Naffah-Mazzacoratti). of the signals from the pre-synaptic terminal to the 32 post-synaptic membrane into the nervous system. 33 The X11 family, also called Munc18 interacting 34 proteins or Mints, are proteins composed of three 35 domains (Okamoto and Sudhof, 1997). The Mints 36 contain an N-terminal sequence, which binds to 37 Munc18-1; an essential protein for synaptic vesicle 38 exocytosis (Okamoto and Sudhof, 1997); a middle 39 domain called phosphotyrosine-binding (PTB) and 40 1 0920-1211/$ – see front matter © 2003 Published by Elsevier B.V. 2 doi:10.1016/j.eplepsyres.2003.10.010 EPIRES 3391 1–9