Serotonin Turnover in Discrete Regions of Young Rat Brain After 24 h REM Sleep Deprivation

The present study has attempted to elucidate the alteration of serotonin turnover after 24 h REM sleep deprivation in different regions in brain of young rat. Sleep deprivation was induced by the inverted flowerpot technique. Results of this study show increased serotonin turnover after 24 h REM sleep deprivation in all the brain regions except in the hypothalamus. The decreased 5-HT ratio shows increased serotonin in the hypothalamus after 24 h sleep deprivation. This study indicates increased activity of serotonergic neurons in the hypothalamus after 24 h sleep deprivation. This also indicates that the hypothalamus plays a role in the immediate compensatory mechanism during 24 h REM sleep deprivation in young rats.     

Sleep Duration Trajectories and Body Composition in Adolescents: Prospective Birth Cohort Study

We aimed to estimate the association between sleep duration trajectories and body composition in adolescents. We used data from participants of the 1993 Pelotas (Brazil) Birth Cohort Study who were later followed up at age 18 years (response rate of 81.3%). At the time, 3974 adolescents had complete data on body composition, which was assessed by air displacement plethysmography. Sleep duration was self-reported by participants at ages 11 and 18 years. Analyses were sex-stratified. The mean sleep duration at 11 years was 9.7 (SD 1.4) and 8.4 (SD 1.9) at 18 years. Sleep duration was dichotomized as inadequate (<8 hours/day) or adequate (≥8 hours/day). Mean body mass, fat mass, and fat-free mass indices at 18 years were 23.4 kg/m² (SD 4.5), 6.1 kg/m² (SD 3.9) and 17.3 kg/m² (SD 2.5), respectively. Girls who reported inadequate sleep duration at 11 years of age, but adequate sleep duration at 18, on average experienced an increase in body mass index (β = 0.39 z-scores; 95% CI 0.13, 0.65), fat mass index (β = 0.30 z-scores; 95% CI 0.07, 0.53), and fat-free mass index (β = 0.24 z-scores; 95% CI 0.08, 0.39) compared to those who had adequate sleep duration at both time points. The results suggest that changes in sleep duration across adolescence may impact body composition in later adolescence and that this may differ by sex.     

ASSOCIATIONS BETWEEN CHRONOTYPE,SLEEP QUALITY,SUICIDALITY, AND DEPRESSIVE SYMPTOMS IN PATIENTS WITH MAJOR DEPRESSION AND HEALTHY CONTROLS

Research interest concerning associations between sleep characteristics and suicidality in psychopathology has been growing. However, possible linkages of suicidality to sleep characteristics in terms of sleep quality and chronotypes among depressive patients have not been well documented. In the current study, the authors investigated the possible effects of sleep quality and chronotype on the severity of depressive symptoms and suicide risk in patients with depressive disorder and healthy controls. The study was conducted on 80 patients clinically diagnosed with major depression and 80 healthy subjects who were demographically matched with the patient group. All participants completed a questionnaire package containing self-report measures, including the Beck Depression Inventory (BDI), Pittsburgh Sleep Quality Index (PSQI), Morningness–Eveningness Questionnaire (MEQ), and Suicide Ideation Scale (SIS), and subjects were interviewed with the suicidality section of the Mini-International Neuropsychiatric Interview (MINI). Results are as follows: (a) logistic regression analyses revealed that poor sleep quality and depression symptom severity significantly predicted onset of major depression; (b) morningness-type circadian rhythm may play as a significant relief factor after onset of major depression; (c) sleep variables of chronotype and sleep quality did not significantly predict suicide ideation after controlling for depressive symptoms in the major depression group; and (d) suicide ideation and poor sleep quality were antecedents of depression symptom severity in patients with major depression, and in healthy controls. Findings are discussed under the theoretical assumptions concerning possible relations between chronotype, sleep quality, depression, and suicidality. (Author correspondence: dryavuzselvi@yahoo.com)     

Day workers suffering from a wider range of sleep problems are more likely to experience suicidality

Both a higher suicide rate and widespread sleep problems are serious health concerns in Japan when compared with those of other countries. We investigated the relationship between suicidal ideation and sleep problems in Japanese day workers using the 3-dimensional sleep scale (3DSS), which measures three sleep elements (phase, quality, and quantity). Data from 635 Japanese day workers (461 mens and 174 womens) were included. The 3DSS was used to assess participants’ sleep condition. Participants were classified into eight sleep types based on scores of phase, quality, and quantity: All Good Sleep, Owl (poor phase), Inefficient (poor quality), Short (poor quantity), Owl + Inefficient (poor phase and quality), Owl + Short (poor phase and quantity), Inefficient + Short (poor quality and quantity), and All Poor Sleep. We assessed participants’ suicidal ideation using question 19 of the self-rating depression scale (SDS); 119 cases (18.7 %) had ratings of 2–4 for this question and were considered to have suicidal ideation. The higher the number of sleep problems, the higher the risk of suicidal ideation compared to sleep types not indicative of problems. All Poor Sleep had the highest risk of the eight sleep types. Individuals with Owl + Short, Inefficient + Short, or All Poor Sleep had a significant risk of suicidal ideation even after adjusting for hopelessness and nightmares. Our findings suggested that sleep problems assessed by the 3DSS were related to suicidal ideation. Analysis of various aspects of sleep could be helpful for suicide prevention.

     

Is insufficient sleep duration associated with suicidal behavior in Korean adolescents?

Sleep and Biological Rhythms - The second leading cause of death among Korean adolescents was suicide in 2014. We assessed the relationship between sleep duration and suicidal behavior (ideation,...     

Individual differences in the sleep/wake cycle of Arctic flexitime workers

Daytime workers tend to have shorter sleep duration and earlier sleep onset during work days than on days off. Large individual differences in sleep onset and sleep duration may be observed on work days, but work usually synchronizes sleep offset to a similar time. The present study describes individual differences in sleep behaviour of 48 daytime workers (25 men, aged 20–58 years) from an iron ore mine in Northern Sweden. The aim of the study was to determine whether differences in sleep patterns during work days were associated with the outcomes of sleepiness and sleep complaints. Cluster analysis was used to group workers into two categories of sleep onset and sleep duration. The “Late Sleep Onset” cluster comprised workers who slept 1.30 h later than the “Early Sleep Onset” cluster (p < 0.0001 for all weekdays). The “Long Sleep Duration” cluster slept 1.10 h longer than the “Short Sleep Duration” cluster (p < 0.0002 for work nights). The “Late Sleep Onset” cluster reported less refreshing sleep (p < 0.01) and had lower sufficient sleep scores (p < 0.01) than the “Early Sleep Onset” cluster. The “Short Sleep Duration” cluster also reported lower scores for sufficient sleep (p < 0.04) than the “Long Sleep Duration” cluster. For combined characteristics (phase and duration), workers with a late phase and short sleep duration reported greater sleep debt and sleepiness than workers with an early phase and short sleep duration (p < 0.02). Work schedule and commuting time modulate both sleep phase and sleep duration independently. Workers, classified as having an intermediate sleep phase preference, can organize their sleep time in order to minimize sleep debt and sleepiness symptoms. Individual differences in sleep phase and duration should be considered when promoting well-being at work even among groups with similar sleep needs. In order to minimize sleep debt and sleepiness symptoms, successful sleep behaviour could be promoted involving extend use of flexitime arrangement (i.e. later starting times) and reduce use of alarm clocks.     

The Impact of Improving Suicide Death Classification in South Korea: A Comparison with Japan and Hong Kong

IntroductionThe suicide rate of South Korea has increased dramatically during the past decades, as opposed to steadily decreasing trends in Japan and Hong Kong. Although the recent increase of suicide in South Korea may be related to changing socioeconomic conditions and other contextual factors, it may also reflect, in part, a reduction of misidentified suicide cases due to improving classification of manner of death.MethodWe compared the annual proportional change of suicide, undetermined death, and accidental death from South Korea with those of Japan and Hong Kong from 1992 to 2011; a greater proportional change of the manner-of-death categories during the period is indicative of a relatively less stable registration and hence a greater potential for misclassification bias on reported suicide trends. Subgroup analyses stratifying the deaths by methods were also conducted. To estimate the impact, the age-standardized rates of these three death categories in each site were calculated.ResultsWe found that, during the 20-year observation period, the proportional change of suicide, undetermined death, and accidental death in South Korea was significantly greater than Japan and Hong Kong. Similar observations were made in subgroup analyses. While death rates of the three manners in Japan and Hong Kong generally moved in a parallel fashion, the increase of suicide in South Korea occurred concomitantly with a significant reduction of its accidental death rate. 43% of the increase in suicides could be attributed to the decrease in accidental deaths, while 57% of the increase could be due to fundamental causes.ConclusionOur data suggest that, during the mid-1990s and after, the increasing burden of suicide in South Korea initially was masked, in part, by misclassification. Thus, the later apparently rapid increase of suicides reflected steadily improving classification of manner of death, as well as a more fundamental increase in the suicide rate.     

Contribution of Serotonergic Transmission to the Motor and Cognitive Effects of High-Frequency Stimulation of the Subthalamic Nucleus or Levodopa in Parkinson’s Disease

Although they are effective at treating the motor impairments that are the core symptoms of Parkinson’s disease, current treatments, namely l-3,4-dihydroxyphenylalanine (l-DOPA), the gold standard medication and high-frequency stimulation of the subthalamic nucleus (HFS-STN), can lead to cognitive and mood alterations. Many of these side effects, such as depression, anxiety and sleep disturbances, could be related to abnormal functioning of the serotonergic system, but much basic research remains to be done. Molecular studies in humans and animal models of the disease have reported diverse drastic changes to the serotonergic system. It has also been shown that the serotonergic system both plays a major role in the mechanism of action of the current therapies and is altered by the therapies. It has been reported that HFS-STN decreases serotonin release in several regions, mostly via inhibition of serotonergic neuron activity. The involvement of serotonergic neurons in l-DOPA treatment is even more significant. First, serotonergic neurons, able to convert exogenous l-DOPA to dopamine, are a major site to release dopamine throughout the brain. Second, the substitution of serotonin by newly synthesized dopamine in serotonin neurons leads to acute and chronic alteration of serotonin release and metabolism. Therefore, both therapeutic approaches, via distinct mechanisms, decrease serotonergic system activity and, rather than alleviating cognitive or mood disorders, tend to aggravate them. Molecular strategies targeting the serotonergic system are being developed and could be decisive in limiting l-DOPA-induced dyskinesia, as well as mood and cognitive symptoms produced by antiparkinsonian therapies.     

Determining expected duration of development under conditions of alternating temperatures

In experiments on development of poikilotherms in alternating temperatures, developmental duration frequently has been compared with some expected duration. The expected durations have generally been calculated erroneously from an average of rates determined at constant temperatures. A method is described to predict correctly the expected duration, based on the average of expected developmental durations. The procedure may also be used to predict correct duration for apparent retarding or accelerating of development under the Kaufmann effect, where rate-temperature relationships are curvilinear. The method is particularly useful where developmental durations are relatively short.     

Promoter and functional polymorphisms of HTR2C and suicide victims

In Europe, the countries with the highest suicide rates form a so-called J-curve, which starts in Finland and extends down to Slovenia—a country with one of the world's highest suicide rates. So far, the strongest association between suicide and genes has been shown for the serotonergic system. A functional polymorphism 68G>C (Cys23Ser) and a promoter polymorphism–995G>A of serotonin receptor 2C (HTR2C) have already been investigated, but no associations with suicide were determined. In the present study 334 suicide victims and 211 controls of Slovenian origin were genotyped for the above-mentioned polymorphisms using standard methods. In the case of the polymorphism–995G>A no association with suicide was found. However, a significant association was observed between female suicide victims and polymorphism 68G>C. The significance remained when we combined alleles of female and male populations. An excess of GG genotype and allele G was observed. However, no statistically important differences were present when only males were analyzed. Haplotype analysis on female population showed marginal association of haplotype G-C with suicide. The present study speaks for the plausible implication of the HTR2C in suicide susceptibility.     

Social and environmental impacts on sleep in captive Asian elephants (Elephas maximus)

Modern zoos strive to improve standards of animal management, husbandry and welfare of their animals as part of a continual evaluation process. Elephants (Elephantidae) have received particular attention in recent years due to the challenge of providing environments which promote natural behavior and opportunities for social interaction. A number of measures have been proposed to measure wellbeing, with sleep quality increasingly being used. Sleep is a vital aspect of life for cell replenishment as well as optimal development of young. Sleep deprivation can lead to immunosuppression and illness; therefore animal managers have a responsibility to ensure they reduce the potential for disturbance through noise, light, or other environmental factors. The social environment also plays an essential role in wellbeing, particularly for species that live in multi-generational family units. In this study the nocturnal behavior of a multi-generational captive herd was observed to determine impacts of husbandry changes on sleep duration and bout length (measured as recumbent rest). As expected, average total duration of sleep was higher in younger elephants and rates were comparable to those reported in other studies of Asian elephants. Overnight access to an outdoor paddock in warmer weather increased overall average bout length of sleep in the herd. Average total duration of sleep also increased for the herd following the movement of an unrelated adult female who had previously shown weak bonds with other herd members. This indicates that social compatibility is a vital component of elephant welfare, impacting not only behavioral interactions but sleep quality and duration.     

Valeriana wallichii root extract improves sleep quality and modulates brain monoamine level in rats

The present study was performed to investigate the effects of Valeriana wallichi (VW) aqueous root extract on sleep-wake profile and level of brain monoamines on Sprague-Dawley rats. Electrodes and transmitters were implanted to record EEG and EMG in freely moving condition and the changes were recorded telemetrically after oral administration of VW in the doses of 100, 200 and 300 mg/kg body weight. Sleep latency was decreased and duration of non-rapid eye movement (NREM) sleep was increased in a dose dependent manner. A significant decrease of sleep latency and duration of wakefulness were observed with VW at doses of 200 and 300 mg/kg. Duration of NREM sleep as well as duration of total sleep was increased significantly after treatment with VW at the doses of 200 and 300 mg/kg. VW also increased EEG slow wave activity during NREM sleep at the doses of 200 and 300 mg/kg. Level of norepinephrine (NE), dopamine (DA), dihydroxyphenylacetic acid (DOPAC), serotonin (5-HT) and hydroxy indole acetic acid (HIAA) were measured in frontal cortex and brain stem after VW treatment at the dose of 200mg/kg. NE and 5HT level were decreased significantly in both frontal cortex and brain stem. DA and HIAA level significantly decreased only in cortex. DOPAC level was not changed in any brain region studied. In conclusion it can be said that VW water extract has a sleep quality improving effect which may be dependent upon levels of monoamines in cortex and brainstem.     

Interacting epidemics? Sleep curtailment, insulin resistance, and obesity

In the last 50 years, the average self-reported sleep duration in the United States has decreased by 1.5-2 hours in parallel with an increasing prevalence of obesity and diabetes. Epidemiological studies and meta-analyses report a strong relationship between short or disturbed sleep, obesity, and abnormalities in glucose metabolism. This relationship is likely to be bidirectional and causal in nature, but many aspects remain to be elucidated. Sleep and the internal circadian clock influence a host of endocrine parameters. Sleep curtailment in humans alters multiple metabolic pathways, leading to more insulin resistance, possibly decreased energy expenditure, increased appetite, and immunological changes. On the other hand, psychological, endocrine, and anatomical abnormalities in individuals with obesity and/or diabetes can interfere with sleep duration and quality, thus creating a vicious cycle. In this review, we address mechanisms linking sleep with metabolism, highlight the need for studies conducted in real-life settings, and explore therapeutic interventions to improve sleep, with a potential beneficial effect on obesity and its comorbidities.     

Relationships between daytime sleepiness and sleep quality,duration, and phase among school-aged children: a cross-sectional survey

A cross-sectional survey was conducted to simultaneously evaluate sleep quality, duration, and phase in school-aged children and correlations between each dimension of sleep and daytime sleepiness were comprehensively examined. A cross-sectional survey was conducted with school-aged children enrolled in four public elementary schools in Joetsu city, Niigata prefecture in Japan (n = 1683). Among the collected responses (n = 1290), 1134 valid responses (547 boys and 587 girls) were analyzed (valid response rate was 87.90%). Data on daytime sleepiness, sleep quality (problems in sleeping at night), sleep duration (the average sleeping time during a week), and sleep phase (sleep timing: bedtime and rising time on weekdays, and sleep regularity: differences in bedtime and rising time between on weekdays and weekends) were collected. The results of multivariate logistic regression analysis indicated that the following dimensions were significantly correlated with daytime sleepiness: the decline in sleep quality [adjusted odds ratio (AOR) = 2.62, 95% confidence interval (CI) = 1.71–4.00], bedtime after 21:30 on weekdays (AOR = 1.58, 95% CI = 1.15–2.18), bedtime delay on weekends, compared to weekdays (AOR = 1.75, 95% CI = 1.27–2.41), and bedtime advance on weekends, compared to weekdays (AOR = 3.33, 95% CI = 1.78–6.20). Sleep dimensions that significantly affected daytime sleepiness in school-aged children are sleep quality, bedtime-timing, and regularity of bedtime. It is important to detect problems in night sleep and establish treatments, as well as to provide support for early bedding on weekdays and for a regular bedtime both on weekdays and on weekends to prevent daytime sleepiness in school-aged children.

     

Differential abnormalities in plasma 5-HIAA and platelet serotonin concentrations in violent suicide attempters: relationships with impulsivity and depression

Brain serotonergic systems may participate in the regulation of mood, impulsivity and aggressive behavior. Because some monoaminergic mechanisms seem to be similar in the central nervous system and peripheral tissues, we tested whether serotonergic or dopaminergic biochemical parameters in peripheral venous blood are related or not to violent suicide behavior.We simultaneously studied plasma serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA) and platelet 5-HT content in patients within 3 days following a violent suicide attempt and in matched healthy controls. We examined their relationship with depression and impulsivity. Twenty seven drug-free suicide attempters and controls were included. Plasma 5-HIAA and platelet 5-HT concentrations were lower in suicide attempters than in controls. Fifteen patients were classified as impulsive (I), including all patients suffering from personality disorder and alcohol abuse, and 12 as non impulsive (NI), mostly melancholics. MADRS scores were similar in both I and NI suicide attempters.When controlling for age, plasma 5-HIAA was lower in I than in NI suicide attempters or controls; these findings are similar to those we observed recently with CSF 5-HIAA in I and NI violent suicide attempters. Contrarily, platelet 5-HT levels were lower in NI than in I patients or controls. Plasma HVA was not associated with suicide behavior. Plasma 5-HIAA concentration was inversely associated with the degree of impulsivity and platelet 5-HT with the intensity of depression. This study indicates that each peripheral serotonergic index is specifically related to a distinct clinical feature and shows differential alteration according to the impulsivity group. In I and NI drug-free violent suicide attempters an inverse figure between plasma 5-HIAA and platelet 5-HT data was observed indicating a non parallelism between these two peripheral variables. Further prospective studies are needed to investigate whether these peripheral serotonergic parameters may be used as helpful early predictors of violent suicide behavior.     

Reduction of REM sleep by a tryptophan-free amino acid diet.

The acute administration of a tryptophan-free amino acid diet to rats has previously been reported to produce a marked reduction in brain serotonin concentrations. The present study examined the effects of such a diet on electroencephalographic sleep measures. There was a decrease in REM sleep and a small increase in nonREM sleep, with no change in total sleep time. In view of these and other observations, the hypothesis that the serotonergic system plays an important role in the maintenance of nonREM sleep should be carefully reevaluated.     

A cross-sectional epidemiological study of the relationship between sleep duration,quality, and rhythm and presenteeism in workers

Sleep and Biological Rhythms - This study aims to examine the relationship of sleep (sleep duration, sleep quality, and sleep rhythm) with presenteeism in workers while controlling for other...     

Gamma-hydroxybutyrate increases tryptophan availability and potentiates serotonin turnover in rat brain

Gamma-hydroxybutyrate (GHB) is both a therapeutic agent and a recreative drug. It has sedative, anxiolytic and euphoric effects. These effects are believed to be due to GHB-induced potentiation of cerebral GABAergic and dopaminergic activities, but the serotonergic system might also be involved. In this study, we examine the effects of pharmacological doses of GHB on the serotonergic activity in rat brain. Administration of 4.0 mmol/kg i.p. GHB to rats induces an accumulation of tryptophan and 5-HIAA (5-hydroxyindole acetic acid) in the frontal cortex, striatum and hippocampus without causing significant change in the tissue serotonin content. In the extracellular space, GHB induced a slight decrease in serotonin release. The tryptophan and 5-HIAA accumulation induced by GHB is mimicked by the GHB receptor agonist para-chlorophenyl-transhydroxycrotonate (NCS-356) and blocked by NCS-382 (6,7,8,9-tetrahydro-5-[H]-benzocycloheptene-5-ol-4-ylidene acetic acid) a selective GHB receptor antagonist. GHB induces the accumulation of either a derivative of or [3H]-tryptophan itself in the extracellular space, possibly by increasing tryptophan transport across the blood-brain barrier. The blood content of certain neutral amino-acids, including tryptophan, is also increased by peripheral GHB administration. Some of the effect of GHB could be reproduced by baclofen and reduced by the GABAB antagonist CGP 35348. Taken together, these results indicate that the GHB-induced stimulation of tissue serotonin turnover may be due to an increase in tryptophan transport to the brain and in its uptake by serotonergic cells. As the serotonergic system may be involved in the regulation of sleep, mood and anxiety, the stimulation of this system by high doses of GHB may be involved in certain neuropharmacological events induced by GHB administration.     

Shift-specific associations between age,chronotype and sleep duration

The objective of this study was to examine the association of age with chronotype and sleep duration in day workers and rotating shift workers, including night shift work. Between October 2012 and February 2015, a cross-sectional study was conducted in a German chemical company. Using the “Munich ChronoType Questionnaire” (MCTQ), data about sleep onset and sleep offset during workdays and work-free days were retrieved and the chronotype was computed during regular voluntary occupational health check-ups. Associations between age and chronotype, as well as sleep duration, were assessed using linear regression analyses. Potential effect modification by the working time system was examined. Within the study period, 4,040 employees (82.3% and 17.7% were engaged in day work and rotating shift work, respectively) completed the questionnaire. Study participants were on average 41.8 years old (Min = 18.0, Max = 65.0, SD = 10.2) and predominantly male (75.4%). Mean chronotype and overall sleep duration was 03:22 (SD = 54 min) and 7.2 h (SD = 1.0 h) respectively. Older age was associated with earlier chronotype and reduced overall sleep duration in both day workers and rotating shift workers (p < 0.001 for all models). Compared to day workers, employees whom engaged in rotating shift work were later chronotypes and had overall a longer sleep duration. With older age, the difference between day and rotating shift workers regarding chronotype increased, while the difference regarding overall sleep duration decreased (p_interaction<0.005 for both models). This finding could indicate that both changes in circadian physiology and exposure to certain work schedules contribute to the age-related changes. Older rotating shift workers, with early chronotypes may have issues with night shifts, while day work and morning shifts may be best compatible to earlier chronotypes. Differences in sleep timing across age groups, might indicate that the same work hours will affect shift workers differently, dependent on their age, suggesting that more flexible and chronotype-adapted work hours could provide useful; especially for older employees. Sleep education in the form of courses and health campaigns could be a way to raise awareness of the importance of a healthy sleep pattern. This could be achieved by learning strategies to better adjust individual sleep patterns to work hours.     

The interaction between TPH2 promoter haplotypes and clinical-demographic risk factors in suicide victims with major psychoses

Tryptophan hydroxylase isoform 2 (TPH2) is a rate-limiting enzyme in the biosynthesis of serotonin (5-HT) and is predominantly localized in the brain. Previous studies have suggested that there is an association between serotonergic dysfunction in the brain and suicidality. This study was designed to examine whether the -473T > A and -8396G > C polymorphisms of the TPH2 gene may be associated with completed suicide in subjects with major psychoses from the Stanley Foundation Brain Bank sample. TPH2 genotypes were determined in 69 subjects with a diagnosis of schizophrenia or bipolar disorder, among which 22 died by suicide. Genomic DNA was amplified by polymerase chain reaction and typed by automated methods. Both markers were found to be in Hardy-Weinberg equilibrium and in strong linkage disequilibrium. No association with history of suicide was found for either polymorphism. Haplotype analysis with EHAP showed no association between completed suicide and haplotype distribution (chi2 = 1.877; 3 df; P = 0.598). Nor was there any association between suicide and these genetic markers even when clinical-demographic factors were considered as covariates in the haplotype analysis. These findings suggest that these 5' marker haplotypes in the TPH2 gene do not influence suicidal behaviour.