Caffeine During Sleep Deprivation: Sleep Tendency and Dynamics of Recovery Sleep in Rats

• Published in: Pharmacology, biochemistry and behavior biochemistry and behavior, 2000, Vol.65 (1), p.155-162
• Main Authors: Wurts, Sarah W, Edgar, Dale M
• Format: Article
• Language: English
• Subjects: Adenosine; Animals; Biological and medical sciences; Caffeine - pharmacology; Circadian Rhythm; Food toxicology; Male; Medical sciences; NREM sleep; Rats; Rats, Wistar; REM sleep; Sleep - drug effects; Sleep Deprivation; Sleep homeostasis; Sleep, REM - drug effects; sleep–wake cycle; Time Factors; Toxicology
• ISSN: 0091-3057; 1873-5177
• DOI: 10.1016/S0091-3057(99)00173-2

The adenosine antagonist caffeine disrupts sleep, but whether caffeine promotes wakefulness by interfering with the expression of sleep or by attenuating sleepiness is unknown. The ability of caffeine to reduce sleep tendency in rats was directly tested by quantifying the number of stimuli needed to maintain wakefulness during sleep deprivation for 6 h after systemic caffeine treatment. In addition, the influence of caffeine on the dynamics between nonrapid-eye-movement (NREM) and rapid-eye-movement (REM) sleep was investigated by comparing the magnitude and time course of the compensatory sleep responses for 42 h postsleep deprivation. Caffeine significantly reduced the attempts to sleep during sleep deprivation, F(1, 9) 8.83, p = 0.0157; 44.9% of vehicle), but did not change compensatory slow-wave activity during recovery sleep. During the initial recovery phase, caffeine suppressed compensatory REM sleep and reduced, but did not block, compensatory NREM sleep duration and continuity. By 42 h postsleep deprivation, the amount of NREM recovered (70.0% of deficit) did not differ from vehicle. In contrast, the REM sleep deficit recovered after caffeine (100%) was more than after vehicle (43.9%). Thus, caffeine slowed the rate of compensatory sleep after sleep deprivation, as indexed by the duration of sleep states and sleep continuity.