title: Functional recovery of the dentate gyrus after a focal lesion is accompanied by structural reorganization in the adult rat.
abstract: The adult brain is highly plastic and tends to undergo substantial reorganization after injury to compensate for the lesion effects. It has been shown that such reorganization mainly relies on anatomical and biochemical modifications of the remaining cells which give rise to a network rewiring without reinstating the original morphology of the damaged region. However, few studies have analyzed the neurorepair potential of a neurogenic structure. Thus, the aim of this work was to analyze if the DG could restore its original morphology after a lesion and to establish if the structural reorganization is accompanied by  behavioral and electrophysiological recovery. Using a subepileptogenic injection of kainic acid (KA), we induced a focal lesion in the DG and assessed in time (1) the loss and recovery of dependent and non dependent DG cognitive functions, (2) the anatomical reorganization of the DG using a stereological probe and immunohistochemical markers for different neuronal maturation stages and, (3) synaptic plasticity as assessed through the induction of in vivo long-term potentiation (LTP) in the mossy fiber pathway (CA3-DG). Our results show that a DG focal lesion with KA leads to a well delimited region of neuronal loss, disorganization of the structure, the loss of associated mnemonic functions and the impairment to elicit LTP. However, behavioral and synaptic plasticity expression occurs in a time dependent fashion and occurs along the morphological restoration of the DG. These results provide novel information on neural plasticity events associated to functional reorganization after damage.
authors.affiliation: Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, AP 70-228, 04510, México, D.F., México. azepeda@biomedicas.unam.mx
authors.forename: Angélica
authors.initials: A
authors.lastname: Zepeda
authors.forename: Andrea
authors.initials: A
authors.lastname: Aguilar-Arredondo
authors.forename: Gabriela
authors.initials: G
authors.lastname: Michel
authors.forename: Laura Elisa
authors.initials: LE
authors.lastname: Ramos-Languren
authors.forename: Martha L
authors.initials: ML
authors.lastname: Escobar
authors.forename: Clorinda
authors.initials: C
authors.lastname: Arias
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D015415:Biomarkers / Q000378:metabolism; D003071:Cognition / Q000187:drug effects*; D018891:Dentate Gyrus / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D018690:Excitatory Amino Acid Agonists / Q000633:toxicity*; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects; D005239:Fear / Q000187:drug effects; D007150:Immunohistochemistry; D007608:Kainic Acid / Q000633:toxicity*; D017774:Long-Term Potentiation / Q000187:drug effects; D008297:Male; D008568:Memory / Q000187:drug effects; D019599:Mossy Fibers, Hippocampal / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology; D009043:Motor Activity / Q000187:drug effects; D009473:Neuronal Plasticity / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D020127:Recovery of Function; D013569:Synapses / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D013997:Time Factors
chemical_list: D015415:Biomarkers; D018690:Excitatory Amino Acid Agonists; D007608:Kainic Acid