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Background: A clear understanding of how general anesthesia affects the brain in patients with Alzheimer disease will be crucial to optimize clinical care. We present results from laboratory investigations with a rat model used to study Alzheimer disease (TgF344-AD) to evaluate the effect of isoflurane anesthesia on the early recovery from anesthesia and postanesthesia sleep architecture in animals that exhibit mild symptoms of cognitive decline.
Methods: We used electroencephalogram (EEG) and electromyogram recordings to distinguish WAKE, NREM, and REM sleep in 8 rats from the transgenic model (AD) group and 7 age-matched control (AC) rats, 17 to 18 months of age. We evaluated the sleep architecture before and after a 1-hour exposure to 1.5% isoflurane. Therefore, we investigated the 12-hour active (lights-off) baseline period before anesthesia and the 5-hour recovery period after anesthesia emergence, and the following 12-hour lights-off period.
Results: The transgenic rats took longer to ambulate after the isoflurane challenge (mean [range] 1256 seconds [838-1565 seconds] vs 799 seconds [530-1125 seconds]; P = .038). There was no significant difference in the proportion of vigilance states during the 5-hour recovery period (ANOVA: WAKE, P = .081; NREM, P = .082; and REM, P = .993). In the first active period after isoflurane, the age-matched control rats showed increased sleep in the first active period after anesthesia compared to WAKE (ANOVA: P < .001), while the transgenic rats showed a higher overall WAKE duration (ANOVA: P < .001) and a more fragmented sleep behavior.
Conclusions: Isoflurane affected the sleep architecture in the transgenic model for studying Alzheimer disease. The prolonged time to ambulation, the more fragmented SLEEP/WAKE behavior, and the relative hyperactivity compared to age-matched control rats may imply that Alzheimer disease diminishes the brain's dynamic range to adapt to altered levels of consciousness.
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http://dx.doi.org/10.1213/ANE.0000000000007717 | DOI Listing |
Nat Sci Sleep
September 2025
Department of Otolaryngology Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, People's Republic of China.
Aim: Obstructive sleep apnea (OSA) is characterized by repetitive upper airway collapse during sleep, resulting in frequent cortical arousals. However, currently used frequency-based arousal metrics do not sufficiently capture the heterogeneity and clinical significance of arousal responses. The odds ratio product (ORP) is a novel electroencephalographic marker that provides a continuous assessment of sleep depth and has the potential to serve as an objective measure of arousal intensity.
View Article and Find Full Text PDFFront Neurosci
August 2025
Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
Introduction: Siestas, or daytime naps, play a critical role in relieving sleep pressure and maintaining physiological balance. However, the effects of siesta disruption remain largely unexplored.
Methods: In this study, we disrupted the natural siesta period (ZT20-23) through daily bedding changes for 2 weeks and examined its effects on overall stress levels, sleep architecture, behavior, and transcriptional responses in the frontal cortex.
NPJ Biol Timing Sleep
September 2025
Healthy Living Spaces Lab, Institute for Occupational, Social and Environmental Medicine, Medical Faculty, RWTH Aachen University, Aachen, Germany.
The retinal photopigment melanopsin is also expressed in subcutaneous white adipose tissue (scWAT). Through melanopsin, light can modulate scWAT metabolism, but its impact on circadian phase is unclear. In vitro exposure of murine scWAT to bright light at different times over 24 h did not elicit phase shifts, unlike the response to corticosterone.
View Article and Find Full Text PDFSleep Adv
July 2025
Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA 02118, United States.
The mismatch between rising sleep need and the fluctuating ability to fall asleep underlies insomnia-the most common sleep disorder-yet remains poorly understood. While sleep need increases steadily with time awake, sleep propensity-the likelihood of transitioning from wake to sleep-follows a bimodal pattern, peaking in the mid-afternoon, dipping in the evening, and rising again near bedtime. Building on our previously developed wave model of sleep dynamics, we extend this homeostatic framework to the waking period and show that it predicts the observed bimodal sleep propensity curve.
View Article and Find Full Text PDFSleep Med Clin
September 2025
Parkinson Foundation Centre of Excellence, King's College Hospital and King's College, London, United Kingdom; King's College Hospital, London, Dubai, UAE; Institute of Psychiatry, Psychology and Neuroscience, King's College, Dementech Clinical Neuroscience Centre London, United Kingdom. Electronic
Sleep dysfunction is dominant in patients on oral dopamine replacement therapies as nighttime therapy is suboptimal and often not attempted. Non oral infusion-based Parkinson's disease (PD) therapies, transdermal therapies, as well as deep brain stimulation (DBS) of the subthalamic nucleus (STN) bridge this gap and provide nighttime cover in most cases in PD. DBS of the STN also show significant improvement in PD sleep scale scores and improvement in sleep quality.
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