Caffeine and light effects on nighttime melatonin and temperature levels in sleep-deprived humans

The effects of caffeine ingestion and exposure to bright light, both separately and in combination, on salivary melatonin and tympanic temperature were assessed in humans. Four treatments during a 45.5 h sleep deprivation period were compared: Dim Light-Placebo, Dim Light-Caffeine, Bright Light-Placebo and Bright-Light Caffeine. The Dim Light-Caffeine condition (200 mg twice each night) relative to the Dim Light-Placebo condition suppressed nighttime melatonin levels and attenuated the normal decrease in temperature. Combining caffeine ingestion with bright light exposure (≥2000 lux) suppressed melatonin and attenuated the normal nighttime drop in temperature to a larger degree than either condition alone; i.e. effects were additive. Circadian effects were also observed in that the amplitude and phase of the temperature rhythm were altered during treatment. These findings establish that the human melatonin system is responsive to caffeine. Other evidence suggests that caffeine may influence melatonin and temperature levels through antagonism of the neuromodulator adenosine.     

490名师范学院大学生失眠状况调查

目的　了解师范学院大学生失眠情况及其分布特征。方法　对上饶师院 4 90名学生进行睡眠和失眠相关问题的问卷调查。结果　 38.0 %的被试报告有失眠现象。男生失眠率显著高于女生 ( χ2 =9.79,P <0 .0 1) ;三年级毕业班学生失眠率高于一年级和二年级学生 ( χ2 =9.86 ,P <0 .0 1) ;文理科学生失眠率差异无显著性。SCL - 90调查结果显示 ,失眠学生躯体化、强迫、人际关系敏感、抑郁、焦虑、恐怖6个因子分和阳性项目数显著高于非失眠者。结论　师范学院大学生失眠现象常见 ,失眠学生心理问题症状较多     

Do weekly and fast-rotating shiftwork schedules differentially affect duration and quality of sleep?

 Characteristics of shiftwork schedules can have distinct impacts on workers’ sleep. This report presents comparisons of the effects of two different shiftwork schedules on duration and quality of the main sleep episodes in comparable worker populations at two different petrochemical plants. No significant differences were found for sleep duration in comparing the two plants. However, within each plant’s shift cycles, morning and night shifts showed shorter sleep durations than all other workdays and days off. Quality of sleep was perceived as lowest for night shifts of both plant schedules, and of lesser quality for weekly than for fast-rotating shifts. These results support recommendations for reducing the number of consecutive nights of shiftwork. However, before recommending any optimal shift schedule, interactions of sleep duration and quality with shift schedules need much further evaluation. Received: 18 December 1995/Accepted: 18 July 1996     

抑郁症的睡眠脑电图与人脑兴奋守恒假说

目的　探索抑郁症状与睡眠脑电图参数的相关性。方法　对 18例抑郁症和 10例正常人评定汉密尔顿抑郁评定量表 (HAMD)和检测睡眠脑电图。结果　HAMD总分与觉醒次数及REM密度分别呈显著正相关 (r分别等于 0 .4 0 8和 0 .4 4 5 ,P均 <0 .0 5 )。结论　抑郁症和正常人的白天中枢抑制与夜间中枢兴奋相关 ,从而支持人脑兴奋守恒假说。     

硕士生睡眠质量状况及其与心理健康的相关研究

目的了解硕士生睡眠质量状况及其与心理健康的关系;为提高硕士生的睡眠质量和心理健康水平提供参考。方法采用匹兹堡睡眠质量指数(PSQI)和症状自评量表(SCL-90)对高校298名硕士生进行睡眠质量和心理健康调查。结果①以PSQI总分≥8作为判断睡眠质量问题的标准,27.4%的硕士生存在睡眠质量问题,睡眠质量不佳主要体现在日间功能障碍(58.4%)、入睡时间(38.6%)、睡眠质量(31%)和睡眠障碍(19.3%)。②一、二年级与三年级在入睡时间上存在显著差异(P<0.05)。公费和自费硕士生在PSQI总分和睡眠效率上存在显著性差异。文科和理科硕士生在催眠药物和日间功能障碍上存在显著性差异。年龄≥30岁和年龄<30岁的硕士生在睡眠效率上存在显著性差异。③硕士生PSQI总分及大多数成份与SCL-90各因子呈显著正相关(P<0.05)。④不同睡眠质量硕士生的心理健康状况分析显示,睡眠质量好、一般和差的硕士生在SCL-90均分及各因子得分上存在显著性差异。结论研究生睡眠质量不尽人意;睡眠质量与心理健康高度相关。各个部门及研究生自身应该引起高度重视,保证良好睡眠,促进身心健康。     

Involvement of prolactin in the REM sleep-promoting activity of systemic vasoactive intestinal peptide (VIP)

The involvement of pituitary prolactin (PRL) in systemic vasoactive intestinal peptide (VIP)-induced sleep was studied. Male rats were implanted with electrodes for EEG-recording, with brain thermistors to record cortical temperature (T_crt) and with chronic intracardial catheters to obtain blood samples and to deliver substances. One group of rats (n = 8) received normal rabbit serum (NS) + physiological saline (SAL) on the baseline day and was injected with NS + VIP on the experimental day. In the other group of rats (n = 6), the baseline day was followed by administration of PRL-antiserum (PRL-AS) + VIP on the experimental day. The sera and VIP or SAL were injected 30 min before and at light onset, respectively. Sleep-wake activity was then recorded for the next 12-h light period. Systemic VIP-stimulated PRL secretion as measured by RIA in serial samples obtained hour 1 postinjection. VIP also elicited selective increases in REM sleep (REMS) in the rats pretreated with NS. T_crt was not affected by VIP. Administration of PRL-AS blocked the increase in circulating levels of free (non-IgG-bound) PRL and prevented VIP-enhanced REMS. Comparisons of the sleep effects of PRL-AS + VIP with the previously reported changes in sleep after PRL-AS alone indicate that PRL has a major role in the mediation of the REMS-promoting activity of systemic VIP. The results suggest that an increased release of endogenous pituitary PRL modulates REMS.     

Increase of prolactin mRNA in the rat hypothalamus after intracerebroventricular injection of VIP or PACAP

Vasoactive intestinal peptide (VIP), the structurally homologous pituitary adenylate cyclase-activating peptide (PACAP) and the pituitary hormone, prolactin (PRL) enhance rapid eye movement sleep (REMS). VIP and PACAP are both inducers of PRL gene expression and release in the pituitary gland. Little is known about PRL regulation in the brain although it is hypothesized that the REMS-promoting activity of i.c.v. administered VIP may be mediated via the activation of cerebral PRL. To test whether VIP or PACAP in fact increase intracerebral mRNA, the peptides (VIP: 30 or 300 pmol; PACAP: 220 pmol) were injected i.c.v. into rats at dark onset. 1 h later, cDNA was synthesized from purified hypothalamic mRNA. Standardized amounts were analysed for PRL using the polymerase chain reaction followed by Southern blotting and hybridization. Compared with β-actin mRNA levels, both VIP and PACAP increased PRL mRNA levels in a dose-dependent fashion though VIP was more effective on a molar basis. The previously reported alternatively spliced PRL mRNA (lacking exon 4) was not detected. The data support the hypothesis that the REMS-promoting activity of central VIP and PACAP might be mediated by cerebral PRL.     

Release of heat-loss responses in paradoxical sleep by thermal loads and by pontine tegmental lesions in cats

Thermoregulatory heat-loss responses at high ambient temperatures were studied in intact cats and those with bilateral electrolytic lesions in the pontine tegmentum during wakefulness (W), slow-wave sleep (SWS), paradoxical sleep (PS) and PS without atonia induced by the lesions. Panting (respiratory rate 90/min) was present W, SWS, and in some cases, during PS. The percentage of the PS episodes with panting was directly related ambient temperature. In intact cats at 30 °C, panting occurred in 8% of the PS episodes; at 35 °C, in 52%, and at 40 °C, in 77%. The percentage of PS episodes with panting higher in the pontine-lesioned cats (90% at 35 °C), probably another indication of the altered thermoregulation of such animals. Thermoregulatory responses to heat load, and thermoregulation in general, have previously been shown to be suppressed in PS. Because hypothalamic thermosensitive neurons lack thermal responses during PS, the partial activation of heat-loss responses observed here may depend upon the function of extrahypothalamic brainstem areas.     

5地市720名高中学生睡眠状况相关因素分析

目的了解省级示范高中学生睡眠状况及相关因素对学生睡眠的影响，为相关部门制订针对性改进措施提供依据。方法采用睡眠状况自评量表（self-rating scale of sleep，SRSS）对省级示范高中学生进行睡眠状况问卷调查，用SPSS 10．0 FOR WINDOWS进行数据的统计与分析。结果发现720名省级示范高中学生睡眠状态异常者占65．42％，显著高于全国常模（45．6％）。其中轻度睡眠问题占57．36％，显著高于全国常模（35．6％）。学业负担过重、缺乏良好的学习习惯、住宿条件差、家庭状况不好、家校距离远和心理问题是导致省级示范高中在校学生睡眠状态异常的主要因素。结论应促进高中生身心健康，提高其学习能力，改善其睡眠状况。     

The effect of oral appliance therapy on blood pressure in patients with obstructive sleep apnea

The objective of the study was to investigate the effects of oral appliance (OA) therapy on ambulatory blood pressure in patients with obstructive sleep apnea (OSA). Eleven OSA patients who received OA therapy were prospectively investigated. Ambulatory blood pressure was measured for 20 h from 4:00 p.m. to 12:00 noon the next day using an ambulatory blood pressure monitor. The Respiratory Disturbance Index (RDI) was measured in the pretreatment and posttitration periods. The OA was titrated to reach a therapeutic jaw position over 2 to 8 months, and posttitration measurements were repeated. At posttitration, the RDI was significantly decreased from a mean (SD) of 24.7 (20.1) to 6.1 (4.5). Significant reductions in diastolic blood pressure (DBP) and mean arterial pressure (MAP) were found for the 20-h periods, and systolic blood pressure (SBP), DBP, and MAP while asleep. The mean values were 79.5 (5.5) to 74.6 (6.0) for DBP and 95.9 (5.4) to 91.2 (5.9) for MAP, for over a 20-h period, and 118.4 (10.0) to 113.7 (9.1) for SBP, 71.6 (8.0) to 67.2 (7.9) for DBP, and 88.4 (8.0) to 83.9 (7.5) for MAP, while asleep. This study suggests that successful OSA treatment with an OA may also be beneficial to lower blood pressure in OSA patients, as previously suggested for nasal continuous positive airway pressure therapy. This study was conducted in the Division of Orthodontics, The University of British Columbia, Canada