Department of Anesthesiology

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Spatial learning and memory deficits following exposure to 24 h of sleep fragmentation or intermittent hypoxia in a rat model of obstructive sleep apnea.

TitleSpatial learning and memory deficits following exposure to 24 h of sleep fragmentation or intermittent hypoxia in a rat model of obstructive sleep apnea.
Publication TypeJournal Article
Year of Publication2009
AuthorsWard CP, McCoy JG, McKenna JT, Connolly NP, McCarley RW, Strecker RE
JournalBrain Res
Volume1294
Pagination128-37
Date Published2009 Oct 19
ISSN1872-6240
KeywordsAnimals, Anoxia, Disease Models, Animal, Learning Disorders, Male, Maze Learning, Memory Disorders, Oxygen, Rats, Rats, Inbred F344, Sleep Apnea, Obstructive, Sleep Deprivation, Space Perception, Time Factors
Abstract

Obstructive sleep apnea is primarily characterized by hypoxemia due to frequent apneic episodes and fragmentation of sleep due to the brief arousals that terminate the apneic episodes. Though neurobehavioral deficits frequently accompany sleep apnea, the relative roles of hypoxia versus sleep fragmentation are difficult to separate in apneic patients. Here, we assessed cognitive function as measured by water maze in the Fischer/Brown Norway (FBN) rat, comparing 24 h of sleep interruption (SI) to 24 h of intermittent hypoxia (IH), in order to dissociate their relative contributions to cognitive impairment. For SI, automated treadmills were used to induce brief ambulation in rats every 2 min, either prior to, or after, initial water maze acquisition training. IH was simulated by cycling environmental oxygen levels between 6% and 19% every 2 min, again either prior to, or after, acquisition. Twenty-four hours of IH exposure had no significant effect on either acquisition or retention, irrespective of whether IH occurred prior to, or after, acquisition. To replicate previous work, another group of rats, exposed to 3 days of IH (10 h/day) prior to acquisition, had impaired performance during acquisition. A comparison of the 24 h IH and 3 day IH findings suggests that a minimum amount of IH exposure is necessary to produce detectable spatial memory impairments. Although SI before acquisition had no effect on acquisition or later retention of the hidden platform location, SI after acquisition robustly impaired retention, indicating that spatial memory consolidation is more susceptible to the effects of sleep disruption than is the acquisition (learning) of spatial information.

DOI10.1016/j.brainres.2009.07.064
Alternate JournalBrain Res.
PubMed ID19643093
PubMed Central IDPMC2762190
Grant ListF32 MH070156 / MH / NIMH NIH HHS / United States
F32 MH070156-01A1 / MH / NIMH NIH HHS / United States
HL060292 / HL / NHLBI NIH HHS / United States
P50 HL060292 / HL / NHLBI NIH HHS / United States
P50 HL060292-02 / HL / NHLBI NIH HHS / United States
P50 HL060292-03 / HL / NHLBI NIH HHS / United States
P50 HL060292-04 / HL / NHLBI NIH HHS / United States
P50 HL060292-05 / HL / NHLBI NIH HHS / United States
P50 HL060292-060002 / HL / NHLBI NIH HHS / United States
P50 HL060292-069003 / HL / NHLBI NIH HHS / United States
P50 HL060292-070002 / HL / NHLBI NIH HHS / United States
P50 HL060292-079003 / HL / NHLBI NIH HHS / United States
P50 HL060292-080002 / HL / NHLBI NIH HHS / United States
P50 HL060292-089003 / HL / NHLBI NIH HHS / United States
P50 HL060292-090002 / HL / NHLBI NIH HHS / United States
P50 HL060292-099003 / HL / NHLBI NIH HHS / United States
P50 HL060292-100002 / HL / NHLBI NIH HHS / United States
P50 HL060292-109003 / HL / NHLBI NIH HHS / United States
T32 HL007901-01 / HL / NHLBI NIH HHS / United States
T32 HL007901-02 / HL / NHLBI NIH HHS / United States
T32 HL007901-02S1 / HL / NHLBI NIH HHS / United States
T32 HL007901-03 / HL / NHLBI NIH HHS / United States
T32 HL007901-04 / HL / NHLBI NIH HHS / United States
T32 HL007901-05 / HL / NHLBI NIH HHS / United States
T32 HL007901-06 / HL / NHLBI NIH HHS / United States
T32 HL007901-07 / HL / NHLBI NIH HHS / United States
T32 HL007901-08 / HL / NHLBI NIH HHS / United States
T32 HL007901-09 / HL / NHLBI NIH HHS / United States
T32 HL007901-10 / HL / NHLBI NIH HHS / United States
T32 HL007901-11 / HL / NHLBI NIH HHS / United States
T32 HL007901-12 / HL / NHLBI NIH HHS / United States
T32 HL07901 / HL / NHLBI NIH HHS / United States