title: The excitement of multiple noradrenergic cell groups in the rat brain related to hyperbaric oxygen seizure.
abstract: The mechanism of oxygen toxicity for central nervous system and hyperbaric oxygen (HBO) seizure has not been clarified. Noradrenergic cells in the brain may contribute to HBO seizure. In this study, we defined the activation of noradrenergic cells during HBO exposure by c-fos immunohistochemistry. Electroencephalogram electrodes were pre-implanted in all animals under general anesthesia. In HBO seizure animals, HBO was induced with 5 atm of 100% oxygen until manifestation of general tonic convulsion. HBO non-seizure animals were exposed to 25 min of HBO. Control animals were put in the chamber for 120 min without pressurization. All animals were processed for c-fos immunohistochemical staining. All animals in the HBO seizure group showed electrical discharge on EEG. In the immunohistochemistry, c-fos was increased in the A1, A2 and A6 cells of the HBO seizure group, and in the A2 and A6 cells of the HBO non-seizure group, yet was extremely low in all three cell types in the control group. These results suggest the participation of noradrenaline in HBO seizure, which can be explained by the early excitement of A1 cells due to their higher sensitivity to high blood pressure, hyperoxia, or by the post-seizure activation of all noradrenergic cells.
authors.affiliation: Department of Anesthesiology and Resuscitology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Japan.
authors.forename: Minako
authors.initials: M
authors.lastname: Arai
authors.forename: Ken
authors.initials: K
authors.lastname: Takata
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Takeda
authors.forename: Satoshi
authors.initials: S
authors.lastname: Mizobuchi
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Morita
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D004569:Electroencephalography; D006931:Hyperbaric Oxygenation / Q000009:adverse effects*; D008297:Male; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism*; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012640:Seizures / Q000139:chemically induced* / Q000503:physiopathology
chemical_list: D016760:Proto-Oncogene Proteins c-fos; D009638:Norepinephrine