title: Signaling function of Na,K-ATPase induced by ouabain against LPS as an inflammation model in hippocampus.
abstract: BACKGROUND
  Ouabain (OUA) is a newly recognized hormone that is synthesized in the adrenal cortex and hypothalamus. Low doses of OUA can activate a signaling pathway by interaction with Na,K-ATPase, which is protective against a number of insults. OUA has central and peripheral anti-inflammatory effects. Lipopolysaccharide (LPS), via toll-like receptor 4 activation, is a widely used model to induce systemic inflammation. This study used a low OUA dose to evaluate its effects on inflammation induced by LPS injection in rats.
  
  
  METHODS
  Adult male Wistar rats received acute intraperitoneal (ip) OUA (1.8 μg/kg) or saline 20 minutes before LPS (200 μg/kg, ip) or saline injection. Some of the animals had their femoral artery catheterized in order to assess arterial blood pressure values before and after OUA administration. Na,K-ATPase activity, cytokine mRNA levels, apoptosis-related proteins, NF-κB activation brain-derived neurotrophic factor BDNF, corticosterone and TNF-α levels were measured.
  
  
  RESULTS
  OUA pretreatment decreased mRNA levels of the pro-inflammatory cytokines, inducible nitric oxide synthase (iNOS) and IL-1β, which are activated by LPS in the hippocampus, but with no effect on serum measures of these factors. None of these OUA effects were linked to Na,K-ATPase activity. The involvement of the inflammatory transcription factor NF-κB in the OUA effect was indicated by its prevention of LPS-induced nuclear translocation of the NF-κB subunit, RELA (p65), as well as the decreased cytosol levels of the NF-κB inhibitor, IKB, in the hippocampus. OUA pretreatment reversed the LPS-induced glial fibrillary acidic protein (GFAP) activation and associated inflammation in the dentate gyrus. OUA also prevented LPS-induced increases in the hippocampal Bax/Bcl2 ratio suggesting an anti-apoptotic action in the brain.
  
  
  CONCLUSIONS
  Our results suggest that a low dose of OUA has an important anti-inflammatory effect in the rat hippocampus. This effect was associated with decreased GFAP induction by LPS in the dentate gyrus, a brain area linked to adult neurogenesis.
authors.affiliation: Molecular Neuropharmacology Laboratory, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, 05508-900, São Paulo, Brazil. paula.f.kinoshita@gmail.com.
authors.forename: Paula Fernanda
authors.initials: PF
authors.lastname: Kinoshita
authors.affiliation: Molecular Neuropharmacology Laboratory, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, 05508-900, São Paulo, Brazil. lidiays@yahoo.com.
authors.forename: Lidia Mitiko
authors.initials: LM
authors.lastname: Yshii
authors.affiliation: Molecular Neuropharmacology Laboratory, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, 05508-900, São Paulo, Brazil. andrea.vasconcelos@gmail.com.
authors.forename: Andrea Rodrigues
authors.initials: AR
authors.lastname: Vasconcelos
authors.affiliation: Molecular Neuropharmacology Laboratory, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, 05508-900, São Paulo, Brazil. amm.orellana@gmail.com.
authors.forename: Ana Maria Marques
authors.initials: AM
authors.lastname: Orellana
authors.affiliation: Molecular Neuropharmacology Laboratory, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, 05508-900, São Paulo, Brazil. limalarissa@yahoo.com.br.
authors.forename: Larissa de Sá
authors.initials: Lde S
authors.lastname: Lima
authors.affiliation: Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil. anapdavel@gmail.com.
authors.forename: Ana Paula Couto
authors.initials: AP
authors.lastname: Davel
authors.affiliation: Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil. lrossoni@icb.usp.br.
authors.forename: Luciana Venturini
authors.initials: LV
authors.lastname: Rossoni
authors.affiliation: Molecular Neuropharmacology Laboratory, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, 05508-900, São Paulo, Brazil. kawamotoe@gmail.com.
authors.forename: Elisa Mitiko
authors.initials: EM
authors.lastname: Kawamoto
authors.affiliation: Molecular Neuropharmacology Laboratory, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, 05508-900, São Paulo, Brazil. cscavone@icb.usp.br.
authors.forename: Cristoforo
authors.initials: C
authors.lastname: Scavone
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects / Q000276:immunology*; D007249:Inflammation / Q000139:chemically induced / Q000188:drug therapy*; D008070:Lipopolysaccharides / Q000276:immunology; D008297:Male; D010042:Ouabain / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000187:drug effects / Q000276:immunology*; D000254:Sodium-Potassium-Exchanging ATPase / Q000187:drug effects / Q000276:immunology*
chemical_list: D004791:Enzyme Inhibitors; D008070:Lipopolysaccharides; D010042:Ouabain; D000254:Sodium-Potassium-Exchanging ATPase