title: Impaired acquisition of spatial memory 2 weeks after isoflurane and isoflurane-nitrous oxide anesthesia in aged rats.
abstract: Aged rats are impaired on a spatial memory task for at least 24-48 h after isoflurane-nitrous oxide anesthesia. In this study, we tested how long the impairment lasts and investigated the role of nitrous oxide. Eighteen-month-old rats were randomized to anesthesia for 2 h with 1.2% isoflurane with or without 70% nitrous oxide or a control group (30% oxygen). Two weeks later, rats were tested daily for 14 days on a 12-arm radial maze. The number of correct choices to first error, total errors, and time to complete the maze were recorded. Rats anesthetized with 1.2% isoflurane with 70% nitrous oxide made fewer correct choices before first error (P < or = 0.05). Trends toward similar results were noted for error rate and time to complete the maze, but these did not achieve statistical significance. Post hoc analysis comparing all anesthetized rats to controls demonstrated that anesthetized rats made fewer correct choices to first error (P < or = 0.05) and took longer to complete the maze (P <or = 0.05). There were no differences in total number of errors (P < or = 0.06). Thus, spatial memory is impaired for 2 wk after general anesthesia in aged rats independent of whether nitrous oxide is used.
authors.affiliation: *Department of Anesthesia, Harvard Medical School, Brigham & Women's Hospital, Boston, Massachusetts; †Department of Psychology, Harvard University, Cambridge, Massachusetts.
authors.forename: Deborah J
authors.initials: DJ
authors.lastname: Culley
authors.forename: Mark G
authors.initials: MG
authors.lastname: Baxter
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Crosby
authors.forename: Rustam
authors.initials: R
authors.lastname: Yukhananov
authors.forename: Gregory
authors.initials: G
authors.lastname: Crosby
mesh_terms: D000375:Aging / Q000523:psychology*; D019162:Anesthetics, Combined / Q000494:pharmacology; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D003071:Cognition / Q000187:drug effects; D007530:Isoflurane / Q000494:pharmacology*; D018782:Maze Learning / Q000187:drug effects; D008568:Memory / Q000187:drug effects*; D009609:Nitrous Oxide / Q000494:pharmacology*; D011597:Psychomotor Performance / Q000187:drug effects; D051381:Rats; D011916:Rats, Inbred F344; D013028:Space Perception / Q000187:drug effects*
chemical_list: D019162:Anesthetics, Combined; D018685:Anesthetics, Inhalation; D007530:Isoflurane; D009609:Nitrous Oxide