title: Modulation of LTP at rat hippocampal CA3-CA1 synapses by direct current stimulation.
abstract: Transcranial direct current stimulation (tDCS) can produce a lasting polarity-specific modulation of cortical excitability in the brain, and it is increasingly used in experimental and clinical settings. Recent studies suggest that the after-effects of tDCS are related to molecular mechanisms of activity-dependent synaptic plasticity. Here we investigated the effect of DCS on the induction of one of the most studied N-methyl-d-aspartate receptor-dependent forms of long-term potentiation (LTP) of synaptic activity at CA3-CA1 synapses in the hippocampus. We show that DCS applied to rat brain slices determines a modulation of LTP that is increased by anodal and reduced by cathodal DCS. Immediate early genes, such as c-fos and zif268 (egr1/NGFI-A/krox24), are rapidly induced following neuronal activation, and a specific role of zif268 in the induction and maintenance of LTP has been demonstrated. We found that both anodal and cathodal DCS produce a marked subregion-specific increase in the expression of zif268 protein in the cornus ammonis (CA) region, whereas the same protocols of stimulation produce a less pronounced increase in c-fos protein expression in the CA and in dentate gyrus regions of the hippocampus. Brain-derived neurotrophic factor expression was also investigated, and it was found to be reduced in cathodal-stimulated slices. The present data demonstrate that it is possible to modulate LTP by using DCS and provide the rationale for the use of DCS in neurological diseases to promote the adaptive and suppress the maladaptive forms of brain plasticity.
authors.affiliation: Istituto di Neurologia, Università Cattolica, L.go A. Gemelli 8, 00168 Rome, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Ranieri
authors.forename: M V
authors.initials: MV
authors.lastname: Podda
authors.forename: E
authors.initials: E
authors.lastname: Riccardi
authors.forename: G
authors.initials: G
authors.lastname: Frisullo
authors.forename: M
authors.initials: M
authors.lastname: Dileone
authors.forename: P
authors.initials: P
authors.lastname: Profice
authors.forename: F
authors.initials: F
authors.lastname: Pilato
authors.forename: V
authors.initials: V
authors.lastname: Di Lazzaro
authors.forename: C
authors.initials: C
authors.lastname: Grassi
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001703:Biophysics; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics / Q000378:metabolism; D056547:CA1 Region, Hippocampal / Q000166:cytology*; D056654:CA3 Region, Hippocampal / Q000166:cytology*; D051766:Early Growth Response Protein 1 / Q000378:metabolism; D004558:Electric Stimulation / Q000379:methods*; D004797:Enzyme-Linked Immunosorbent Assay; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects; D018756:GABA Antagonists / Q000494:pharmacology; D066298:In Vitro Techniques; D017774:Long-Term Potentiation / Q000187:drug effects / Q000502:physiology*; D008297:Male; D010751:Phosphopyruvate Hydratase / Q000378:metabolism; D010852:Picrotoxin / Q000494:pharmacology; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D017966:Pyramidal Cells / Q000187:drug effects / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013569:Synapses / Q000187:drug effects / Q000502:physiology*
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D051766:Early Growth Response Protein 1; D018756:GABA Antagonists; D010751:Phosphopyruvate Hydratase; D010852:Picrotoxin; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; C486110:Egr1 protein, rat