Melatonin and 5-methoxytryptophol (5-ML) in nervous and/or neurosensory structures of a gastropod mollusc (Helix aspersa maxima): synthesis and diurnal rhythms

Daily patterns of melatonin and 5-methoxytryptophol (5-ML) concentrations and of aryl alkylamine N-acetyltransferase (AA-NAT) and hydroxyindole-O-methyltransferase (HIOMT) activities have been measured in the cerebroid ganglions, visceral ganglions, and ocular tentacles of the gastropod mollusc Helix aspersa maxima. Melatonin concentrations are very low in all the studied structures, except a small peak at the end of the night in the cerebroid ganglions. 5-ML, which is quite undetectable in the cerebroid and visceral ganglions, shows clear daily variations in the ocular tentacles with low values in the middle of the light period and high values during the night. These results are opposite to what is known on daily variations of 5-ML in vertebrates. AA-NAT activity was not detected, while the presence of an HIOMT-like activity supports the hypothesis that 5-ML is synthesized in the ocular tentacles. The temporal relationships existing between the 5-ML rhythm in the ocular tentacles and the hemolymph suggest that 5-ML could be released in the general circulation. These preliminary results suggest that 5-ML could be an informative molecule involved in adaptative processes in the snail and they reinforce the hypothesis that the different 5-methoxyindoles could be implicated in the integration of environmental information.     

高血压病合并阻塞性睡眠呼吸暂停的血压昼夜节律研究

研究阻塞性睡眠呼吸暂停对高血压病患血压昼夜节律的影响。方法１８４例研究对象根据诊所血压、２４小时动态血压和多导睡眠图监测结果分为正常对照组、高血压组、高血压病合并轻度或中重度睡眠呼吸暂停组。比较睡眠呼吸暂停指数、睡眠结构对血压昼夜节律的影响。     

Ultradian and circadian modulation of dream recall: EEG correlates and age effects

Dreaming occurs during non-rapid eye movement (NREM) and rapid eye movement (REM) sleep, which both are regulated by homeostatic, ultradian, and circadian processes. However, the magnitude of how ultradian REM and NREM sleep and its EEG correlates impact onto dream recall remains fairly unknown. In this review, we address three questions: 1. Is there an ultradian NREM–REM sleep modulation in successful dream recall, which is gated by the circadian clock? 2. What are the key electrophysiological correlates that account for dream recall during NREM and REM sleep and 3. Are there age-related changes in the ultradian and circadian regulation in dream recall and its electrophysiological correlates? Knowledge on the specific frequency and topography NREM and REM sleep differences prior to dream recall may pinpoint to the cerebral correlates that account for this cognitive process, and hint to their possible physiological meaning.     

The influence of intensity and timing of daily light exposure on subjective and objective sleep in adolescents with an evening circadian preference

Study objectivesThe aim of the present study is to examine the relationship between light and sleep, in adolescents with an evening circadian preference.MethodsFor a period of seven days, ninety-nine adolescents wore a wrist actigraph to assess light exposure and objective sleep and completed a sleep diary to assess subjective sleep.ResultsLower average light intensity across the preceding 24 h was associated with a later sleep onset (p < 0.01) and a later next-day sleep offset (p < 0.05). A later time of last exposure to more than 10 lux was associated with a later sleep onset (p < 0.001) and a shorter objective total sleep time (p < 0.001), as well as a later bedtime (p < 0.001) and a shorter subjective total sleep time (p < 0.001). Furthermore, exploratory analyses found that lower average early morning light exposure (between 4 and 9 AM) was associated with later sleep onset (p < 0.05), a later next-day sleep offset (p < 0.05), and a later next-day waketime (p < 0.01), lower average afternoon light exposure (between 2 and 7 PM) was associated with a later next-day sleep offset (p < 0.05), and lower average evening light exposure (between 7 PM and 12 AM) was associated with longer subjective total sleep time (p < 0.01).ConclusionThis study highlights the importance of light exposure, particularly the timing of light exposure, for establishing healthy patterns of sleep among adolescents with a propensity for a delayed bedtime and waketime. These findings provide additional evidence for targeting light exposure when designing interventions to improve adolescent sleep.     

Sleep habits and circadian preferences in school-aged children attending a Mexican double-shift school system

ObjectiveTo determine the differences between sleep habits and circadian preference in school-aged children attending a Mexican double-shift school system.MethodsThis cross-sectional study consisted of 400 elementary public-school children (mean age = 10.77, SD = 0.70 y, from fourth, fifth and sixth grades) in Reynosa, Tamaulipas, in northeastern Mexico. Attending a double-shift school system: 200 from the morning shift and 200 in the afternoon shift. Specific questions regarding sleep habits were collected and for circadian preference, the Morningness-Eveningness Scale for Children (MESC) was used.ResultsMultivariate analysis reported no sex differences. Children attending at the morning shift during weekdays rose earlier, reported shorter time in bed and earlier midpoint of sleep than those in the afternoon shift. On weekends, morning shift children went to bed later than afternoon shift. Morning shift reported greater social jetlag, shorter average sleep length and more sleep deficit than afternoon shift. During weekdays and weekends evening type children went to bed later, rose later and reported later midpoint of sleep. Also, evening type reported more social jetlag than morning types.ConclusionThis study suggests that early school start times can have a detrimental effect on Mexican children. Moreover, the morning shift children may be at more risk of poor health due to the higher social jetlag, as well as a higher tendency to be sleep deprived. On the other hand, the afternoon shift represents an important social environment that allows children to follow their natural physiological needs and a more optimal sleep health.     

Circadian typology and implications for adolescent sleep health. Results from a large,cross-sectional,school-based study

Study objectivesTo investigate circadian typology in a large, representative sample of Norwegian adolescents, and its implications for sleep health.MethodsThe sample included 3920 1^st year high school students aged 16–17 years. Respondents completed a web-based survey, including the short version of the Horne-Ostberg Morningness-Eveningness Questionnaire (rMEQ), the Munich Chronotype Questionnaire (MCTQ) and items on sleep-related behaviors (eg electronic media usage in bed, consumption of caffeinated beverages), sleep beliefs and daytime sleepiness. Data were analyzed using one-way ANOVAs and Chi-squared tests.ResultsIn all, 7.8% were categorized as morning, 52.3% as intermediate and 39.9% as evening types, respectively. Evening types had later sleep timing, longer sleep latency, more social jetlag and shorter school day sleep duration than morning types, with intermediate types displaying a sleep pattern between these two extremes. None of the circadian types met the minimum recommended amount of sleep on school nights (ie 8+ hours), and only morning types had a mean sleep duration of 7+ hours (7:19 h, nearly 1 h more than evening types who slept 6:20 h, p < 0.001). Evening types reported more use of electronic media in bed, more consumption of caffeinated beverages and more daytime sleepiness than the other circadian types. They were also less satisfied with their school day sleep duration and perceived it more difficult to change their sleep pattern.ConclusionsResults from this study suggest that eveningness represents a sleep health challenge for older adolescents.     

24-hour pattern of circulating prolactin and growth hormone levels and submaxillary lymph node immune responses in growing male rats subjected to social isolation

To assess the effect of social isolation of growing rats on 24-h rhythmicity of circulating prolactin and growth hormone (GH) levels and submaxillary lymph node immune responses, male Wistar rats were either individually caged or kept in groups (4–5 animals per cage) for 30 d starting on d 35 of life. Plasma prolactin and GH levels, and submaxillary lymph node lymphocyte subset populations, interferon (IFN)-γ release and mitogenic responses to concanavalin A (Con A) and lipopolysaccharide (LPS) were determined at six time intervals during the 24 h span. Social isolation brought about changes in mean values and 24-h pattern of plasma prolactin and GH levels and lymph node immune responses. After isolation, prolactin and GH mean values decreased, and lymph node T, B, non T-non B, CD8⁺, and CD4⁺-CD8⁺ cells augmented, whereas lymph node CD4⁺/CD8⁺ ratio, IFN-γ release and mitogenic responses decreased. Social isolation resulted in disruption of 24 h rhythmicity of every immune parameter tested. CD4⁺/CD8⁺ ratio, IFN-γ release and Concanavalin A (Con A) and lipopolysaccharide (LPS) responses correlated significantly with plasma prolactin or GH levels while T/B ratio correlated with plasma prolactin levels only. B, non T-non B, and CD4⁺-CD8⁺ cells correlated negatively with plasma prolactin. Modifications in mean value and 24-h rhythmicity of plasma prolactin and GH levels are presumably involved in the effect of social isolation on immune responsiveness.     

时钟节律对肠癌术后胃肠功能的影响及可能的机制

目的观察一天中不同时间进行肠道手术对患者术后胃肠功能恢复和炎症反应的影响,并探讨褪黑素在其中的作用。方法选择75例择期开腹行结直肠癌根治术患者,根据手术开始时间分为三组,CT1(8:00~14:00)和CT2组(14:00~20:00)患者各30例,CT3组(20:00~2:00)患者15例,三组患者均选择全凭静脉麻醉。在围术期不同时点抽取患者外周血检测褪黑素、C反应蛋白(CRP)、白介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)水平,同时观察患者术后胃肠道功能恢复情况及术后并发症发生率。结果 CT3组患者麻醉前即刻褪黑素水平比手术即日晨8点明显升高[(23.46±4.13)pg/m L比(16.73±3.77)pg/m L,P0.05],且明显高于CT1组[(16.30±3.73)pg/m L]及CT2组[(15.75±3.54)pg/m L]麻醉前即刻(P0.05);CT3组术后肛门排气时间[(73.2±6.3)h]、排便时间[(95.6±8.3)h]、胃液引流量[(452.3±93.7)m L]均明显高于CT1组[(66.7±5.6)h、(8.75±7.4)h、(310.4±78.9)m L]及CT2组[(65.3±6.2)h、(86.7±6.8)h、(307.5±80.1)m L](P0.05),CT3组术后感染发生率明显高于CT1组及CT2组(53.3%比16.7%、20.0%,P0.05);CT3组患者术后1、3天的CRP、IL-6、TNF-α水平明显高于CT1组及CT2组[术后1天CRP:(95.6±16.9)mg/L比(78.8±16.4)mg/L、(80.3±15.7)mg/L;IL-6:(124.7±26.9)pg/L比(104.5±24.3)pg/L、(107.5±22.8)pg/L;TNF-α:(379.8±94.6)pg/L比(317.5±83.1)pg/L、(313.2±86.4)pg/L。术后3天CRP:(78.8±15.4)mg/L比(66.3±12.9)mg/L、(67.6±13.5)mg/L;IL-6:(106.3±22.5)pg/L比(92.7±20.4)pg/L、(93.2±21.0)pg/L;TNF-α:(294.3±78.7)pg/L比(244.9±72.0)pg/L、(245.7±71.6)pg/L,P0.05]。结论同一天中不同时间进行肠癌手术会影响手术预后,晚上进行的肠道手术术后炎症反应较强,术后胃肠功能恢复较慢,术后感染发生率较高,其原因可能与褪黑素对时钟节律的调节有关。     

Circadian disruption in the pathogenesis of metabolic syndrome

Metabolic syndrome is a multifactorial process induced by a combination of genetic and environmental factors and recent evidence has highlighted that circadian disruption and sleep loss contribute to disease pathogenesis. Emerging work in experimental genetic models has provided insight into the mechanistic basis for clock disruption in disease. Indeed, disruption of the clock system perturbs both neuroendocrine pathways within the hypothalamus important in feeding and energetics, in addition to peripheral tissues involved in glucose and lipid metabolism. This review illustrates the impact of molecular clock disruptions at the level of both brain and behavior and peripheral tissues, with a focus on how such dysregulation in turn impacts lipid and glucose homeostasis, inflammation and cardiovascular function. New insight into circadian biology may ultimately lead to improved therapeutics for metabolic syndrome and cardiovascular disease in humans.