• Sleep Medicine and Psychophysiology
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• v.26 no.1
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• pp.5-15
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• 2019

Chronotype (CT) is defined as an inter-individual difference in sleep-wake cycles and daily activities. Previous studies have suggested that this individual difference can influence our biological and psychological functioning. Literature regarding the psychometric properties and validity of CT measures are reviewed. We provide an overview of biological indicators (sleep-wake cycle, body temperature, cortisol, and melatonin) that are used for distinguishing two chronotypes: morningness (MT) and eveningness (ET). We also review the differences between CT in relation to personality traits and the occurrence of psychopathology. In addition, the methodological limitations of studies on CT are discussed. Finally, future research directions in terms of CT are proposed.

• Biomolecules & Therapeutics
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• v.25 no.6
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• pp.586-592
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• 2017

Sinomenium acutum has been long used in the preparations of traditional medicine in Japan, China and Korea for the treatment of various disorders including rheumatism, fever, pulmonary diseases and mood disorders. Recently, it was reported that Sinomenium acutum, has sedative and anxiolytic effects mediated by GABA-ergic systems. These experiments were performed to investigate whether sinomenine (SIN), an alkaloid derived from Sinomenium acutum enhances pentobarbital-induced sleep via ${\gamma}$-aminobutyric acid (GABA)-ergic systems, and modulates sleep architecture in mice. Oral administration of SIN (40 mg/kg) markedly reduced spontaneous locomotor activity, similar to diazepam (a benzodiazepine agonist) in mice. SIN shortened sleep latency, and increased total sleep time in a dose-dependent manner when co-administrated with pentobarbital (42 mg/kg, i.p.). SIN also increased the number of sleeping mice and total sleep time by concomitant administration with the sub-hypnotic dosage of pentobarbital (28 mg/kg, i.p.). SIN reduced the number of sleep-wake cycles, and increased total sleep time and non-rapid eye movement (NREM) sleep. In addition, SIN also increased chloride influx in the primary cultured hypothalamic neuronal cells. Furthermore, protein overexpression of glutamic acid decarboxylase ($GAD_{65/67}$) and $GABA_A$ receptor subunits by western blot were found, being activated by SIN. In conclusion, SIN augments pentobarbital-induced sleeping behaviors through $GABA_A$-ergic systems, and increased NREM sleep. It could be a candidate for the treatment of insomnia.

• Biomolecules & Therapeutics
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• v.25 no.2
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• pp.105-111
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• 2017

It has been known that RA, one of major constituents of Perilla frutescens which has been used as a traditional folk remedy for sedation in oriental countries, shows the anxiolytic-like and sedative effects. This study was performed to know whether RA may enhance pentobarbital-induced sleep through ${\gamma}-aminobutyric$ acid $(GABA)_A-ergic$ systems in rodents. RA (0.5, 1.0 and 2.0 mg/kg, p.o.) reduced the locomotor activity in mice. RA decreased sleep latency and increased the total sleep time in pentobarbital (42 mg/kg, i.p.)-induced sleeping mice. RA also increased sleeping time and number of falling sleep mice after treatment with sub-hypnotic pentobarbital (28 mg/kg, i.p.). In electroencephalogram (EEG) recording, RA (2.0 mg/kg) not only decreased the counts of sleep/wake cycles and REM sleep, but also increased the total and NREM sleep in rats. The power density of NREM sleep showed the increase in ${\delta}-waves$ and the decrease in ${\alpha}-waves$. On the other hand, RA (0.1, 1.0 and $10{\mu}g/ml$) increased intracellular $Cl^-$ influx in the primary cultured hypothalamic cells of rats. RA (p.o.) increased the protein expression of glutamic acid decarboxylase ($GAD_{65/67}$) and $GABA_A$ receptors subunits except ${\beta}1$ subunit. In conclusion, RA augmented pentobarbital-induced sleeping behaviors through $GABA_A-ergic$ transmission. Thus, it is suggested that RA may be useful for the treatment of insomnia.

• Journal of Ginseng Research
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• v.34 no.4
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• pp.304-313
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• 2010

This study was undertaken to discover the effects and possible mechanisms of the effect of red ginseng extract (RGE) on spontaneous sleep. The effects of a low dose (10 mg/kg) and a high dose (200 mg/kg) of RGE were compared in rats. After recovery from a surgical operation enabling electroencephalograms recordings, rats were administered RGE orally. RGE was administered orally for 1 day or once per day for 5 days in either 10 or 200 mg/kg doses. Polygraphic signs were recorded for 12 h after oral administration of RGE. Both treatment with a large dose (200 mg/kg) of RGE for one day and treatment with either a large or a small dose for 5 days reduced the number of sleep.wake cycles. Daily treatment with RGE (either 10 or 200 mg/kg) for 5 days augmented NREM and total sleep, but reduced wakefulness. Delta wave activity recorded during non-REM (NREM) sleep and REM sleep was increased after one treatment with RGE (either 10 or 200 mg/kg). Delta wave activity during NREM was enhanced after daily treatment with RGE (either 10 or 200 mg/kg) for 5 days. Both alpha and beta subunits of the $\gamma$-aminobutyric acid $(GABA)_A$ receptor were significantly over-expressed in the hypothalamus of the RGE-treated groups. Moreover, the expression of glutamic acid decarboxylase was also increased in the hypothalamus. These results demonstrate that RGE may regulate spontaneous sleep via $GABA_A$ergic systems.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.1 no.1
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• pp.77-97
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• 1994

The circadian system represents a temporal order which is mediated by the mutual coupling of oscillators and by the synchronizing effects of zeitgebers. It is known that well-being of man depends partly on the maintenance of this order, and that repeated or long lasting disturbances to it such as shift work will Cause harmful effects. This study was a quasi-experimental study to test the effect of shift directions for the clinical nurses on the circadian rhythm. Fourteen nurses working at the general units of Y hospital were selected according to the established criteria. Fourteen subjects were assigned to a weekly shift but the directions of shift work were phase delay first and then phase advance or vice versa. Oral temperature, total sleeping time, frequency of sleep-wake cycle, fatigue, mental performance, and physical symptom were measured during these days except holidays. The data collection period was from April 26, 1993 to July 3, 1993. MANOVA and Wilcoxon signed rank test were used for statistical analysis. The results are summarized as follows. 1. Having worked on evening and night shifts in either phase delay or phase advance schedules, temperature rhythms of shift workers were gradually adapted to the new sleep-wake cycles. A complete adaptation to work on the night shift was achieved the sixth day of the night shift in the phase delay schedule compared to the partial adaptation to the work on the night shift in the phase advance schedule. Accordingly, by putting evening shift between day and night shifts, it will be possible for circadian rhythm to adapt easily to the night shift. 2. There were differences in the total sleeping time, frequency of steep-wake cycle, fatigue, and physical symptom except for mental performance between night shift and day, evening shift. This indicates further that shift workers working on the night shift have a hard time adapting to the shift work compared to the other shifts. 3. Evaluating all the acrophases of temperature rhythm either in phase delay or phase ad-vance schedules, it was shown that night to evening shift in the phase ad-vance schedule revealed the smallest phase move. Also phase advance schedule showed poorer adaptation to shift work than phase delay schedule in connection with total sleeping time, frequency of sleep-wake cycle, fatigue, mental performance, and physical symptom. It is suggested, taken together, these findings reflect that phase delay schedule facilitated the degree of adjustment to the shift work compared to the phase advance schedule.

• The Korean Journal of Physiology and Pharmacology
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• v.21 no.1
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• pp.27-36
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• 2017

Angelicae Gigantis Radix (AGR, Angelica gigas) has been used for a long time as a traditional folk medicine in Korea and oriental countries. Decursinol angelate (DCA) is structurally isomeric decursin, one of the major components of AGR. This study was performed to confirm whether DCA augments pentobarbital-induced sleeping behaviors via the activation of $GABA_A$-ergic systems in animals. Oral administration of DCA (10, 25 and 50 mg/kg) markedly suppressed spontaneous locomotor activity. DCA also prolonged sleeping time, and decreased the sleep latency by pentobarbital (42 mg/kg), in a dose-dependent manner, similar to muscimol, both at the hypnotic (42 mg/kg) and sub-hypnotic (28 mg/kg) dosages. Especially, DCA increased the number of sleeping animals in the sub-hypnotic dosage. DCA (50 mg/kg, p.o.) itself modulated sleep architectures; DCA reduced the counts of sleep/wake cycles. At the same time, DCA increased total sleep time, but not non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. In the molecular experiments. DCA (0.001, 0.01 and $0.1{\mu}g/ml$) increased intracellular Cl- influx level in hypothalamic primary cultured neuronal cells of rats. In addition, DCA increased the protein expression of glutamic acid decarboxylase ($GAD_{65/67}$) and $GABA_A$ receptors subtypes. Taken together, these results suggest that DCA potentiates pentobarbital-induced sleeping behaviors through the activation of $GABA_A$-ergic systems, and can be useful in the treatment of insomnia.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.3
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• pp.331-335
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• 2010

Previous low-energy time synchronization methods have mainly focused on reducing the number of transmission or reception packets. However, this paper proposes a method that reduces the percentage of time a node has to be awake (the duty cycle), assuming that a periodic sleep-wake cycle is used to conserve energy. Based on our experience with actual WSN devices, a system model is proposed, and the potential performance of the proposed method, with different parameter values, is analyzed. To further demonstrate the feasibility of our method, experiments were conducted using nine WSN devices in a $3{\times}3$ grid network topology. The results show the average synchronization error is 107.57 $\mu{s}$ in duty cycle 5% and synchronization period 10 sec, and 130 $\mu{s}$ in duty cycle 2.5% and synchronization period 20 sec.

• Journal of Ginseng Research
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• v.45 no.1
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• pp.183-190
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• 2021

Background: The circadian rhythm is the internal clock that controls sleep-wake cycles, metabolism, cognition, and several processes in the body, and its disruption has been associated with aging. The differentiated embryo chondrocyte (Dec) gene is related to circadian rhythm. To our knowledge, there are no reports of the relationship between dec gene expression and KRG effect. Therefore, we treated Dec gene knockout (KO) aging mice with KRG to study anti-aging related effects and possible mechanisms. Methods: We evaluated KRG and expression of Dec genes in an ototoxicity model. Dec genes expression in livers of aging mice was further analyzed. Then, we assessed the effects of DEC KO on hearing function in mice by ABR. Finally, we performed DNA microarray to identify KRG-related gene expression changes in mouse liver and assessed the results using KEGG analysis. Results: KRG decreased the expression of Dec genes in ototoxicity model, which may contribute to its anti-aging efficacy. Moreover, KRG suppressed Dec genes expression in liver of wild type indicating inhibition of senescence. ABR test indicated that KRG improved auditory function in aging mouse, demonstrating KRG efficacy on aging related diseases. Conclusion: Finally, in KEGG analysis of 238 genes that were activated and 158 that were inhibited by KRG in DEC KO mice, activated genes were involved in proliferation signaling, mineral absorption, and PPAR signaling whereas the inhibited genes were involved in arachidonic acid metabolism and peroxisomes. Our data indicate that inhibition of senescence-related Dec genes may explain the anti-aging efficacy of KRG.