title: [The study of the anesthetic action of halothane on the rat spinal cord by fos immunoreactivity].
abstract: This study was performed to examine the anesthetic action of halothane on the spinal cord of rats by using fos immunoreactivity, a marker for neuronal activity following noxious stimulation. Sprague-Dawley rats were injected with 150 microliters of 5% formalin subcutaneously into the left hindpaw. Control group (n = 5) received 100% oxygen for 3 hours after injection. 1 MAC group (n = 5) and 1.5 MAC group (n = 5) of rats were anesthetized with 1 MAC or 1.5 MAC halothane, respectively, for 3 hours after injection. The number of fos immunoreactive cells was counted in the lumbar spinal cord of each rat. All rats showed escape reactions against noxious stimulation in the control group. In the 1 MAC and 1.5 MAC groups, two of five rats showed response to noxious stimulation and the another three showed no response, respectively. There was profound relation between the responding rats and the expression of fos immunoreactivity in the spinal dorsal horn. The number of fos immunoreactive cells decreased in the cord of rats that showed no response to noxious stimulation by halothane 1 or 1.5 MAC. These findings suggest that halothane has analgesic action on spinal nociceptive neurons in the rats on the condition that its reactions to noxious stimulation are suppressed by halothane of any concentration.
authors.affiliation: Department of Anesthesiology, Fukushima Medical University School of Medicine.
authors.forename: Y
authors.initials: Y
authors.lastname: Fukada
authors.forename: M
authors.initials: M
authors.lastname: Otsuki
authors.forename: C
authors.initials: C
authors.lastname: Tase
mesh_terms: D000769:Anesthesia, Inhalation; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D015415:Biomarkers / Q000032:analysis; D004305:Dose-Response Relationship, Drug; D006221:Halothane / Q000494:pharmacology*; D008297:Male; D009474:Neurons / Q000737:chemistry; D009619:Nociceptors / Q000737:chemistry; D016760:Proto-Oncogene Proteins c-fos / Q000032:analysis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000737:chemistry* / Q000166:cytology; D009435:Synaptic Transmission / Q000187:drug effects
chemical_list: D018685:Anesthetics, Inhalation; D015415:Biomarkers; D016760:Proto-Oncogene Proteins c-fos; D006221:Halothane