title: Mild hypoxia preconditioning prevents impairment of passive avoidance learning and suppression of brain NGFI-A expression induced by severe hypoxia.
abstract: The aim of this work was to study effects of mild preconditioning hypobaric hypoxia (380 Torr for 2 h, repeated 3 or 6 times spaced at 24 h) on brain NGFI-A immunoreactivity and passive avoidance (PA) behavior in rats exposed to severe hypoxia (160 Torr for 3 h). Severe hypobaric hypoxia produced extensive neuronal loss in hippocampal CA1, while the preceding hypoxic preconditioning had clear protective effect on neuronal viability of vulnerable hippocampal cells. Besides, the hypoxic preconditioning prevented impairment of acquisition and retention of PA caused by severe hypoxia. The six-trial hypobaric preconditioning was more effective in protection against PA learning deficits in severe hypoxia exposed rats than the three-trial preconditioning. The preconditioning up-regulated severe hypoxia-suppressed neocortical and hippocampal expression of NGFI-A, suggesting a possible role for NGFI-A in the neuroprotective mechanisms activated by hypoxic preconditioning.
authors.affiliation: Laboratory of Neuroendocrinology, Pavlov Institute of Physiology Russian Academy of Sciences, 199034 St. Petersburg, Russia.
authors.forename: Elena
authors.initials: E
authors.lastname: Rybnikova
authors.forename: Ludmila
authors.initials: L
authors.lastname: Vataeva
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Tyulkova
authors.forename: Tatiana
authors.initials: T
authors.lastname: Gluschenko
authors.forename: Vladimir
authors.initials: V
authors.lastname: Otellin
authors.forename: Markku
authors.initials: M
authors.lastname: Pelto-Huikko
authors.forename: Michail O
authors.initials: MO
authors.lastname: Samoilov
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001362:Avoidance Learning / Q000502:physiology*; D001522:Behavior, Animal; D002470:Cell Survival; D003213:Conditioning, Psychological / Q000502:physiology; D004268:DNA-Binding Proteins / Q000378:metabolism*; D051766:Early Growth Response Protein 1; D005786:Gene Expression Regulation / Q000502:physiology; D002534:Hypoxia, Brain / Q000378:metabolism / Q000503:physiopathology* / Q000517:prevention & control; D017874:Immediate-Early Proteins / Q000378:metabolism*; D007150:Immunohistochemistry / Q000379:methods; D019194:Ischemic Preconditioning / Q000379:methods*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D051766:Early Growth Response Protein 1; C486110:Egr1 protein, rat; D017874:Immediate-Early Proteins; D014157:Transcription Factors