RESUMEN
Evidence on the association between insomnia symptoms and mortality is limited and inconsistent. This study examined the association between insomnia symptoms and mortality in cohorts from three countries to show common and unique patterns. The Finnish cohort comprised 6605 employees of the City of Helsinki, aged 40-60 years at baseline in 2000-2002. The Norwegian cohort included 6236 participants from Western Norway, aged 40-45 years at baseline in 1997-1999. The Lithuanian cohort comprised 1602 participants from the City of Palanga, aged 35-74 years at baseline in 2003. Mortality data were derived from the Statistics Finland and Norwegian Cause of Death Registry until the end of 2012, and from the Lithuanian Regional Mortality Register until the end of 2013. Insomnia symptoms comprised difficulties initiating sleep, nocturnal awakenings, and waking up too early. Covariates were age, marital status, education, smoking, alcohol, physical inactivity, obesity, diabetes, cardiovascular diseases, depression, shift work, sleep duration, and self-rated health. Cox regression analysis was used. Frequent difficulties initiating sleep were associated with all-cause mortality among men after full adjustments in the Finnish (hazard ratio 2.51; 95% confidence interval 1.07-5.88) and Norwegian (hazard ratio 3.42; 95% confidence interval 1.03-11.35) cohorts. Among women and in Lithuania, insomnia symptoms were not statistically significantly associated with all-cause mortality after adjustments. In conclusion, difficulties initiating sleep were associated with mortality among Norwegian and Finnish men. Variation and heterogeneity in the association between insomnia symptoms and mortality highlights that further research needs to distinguish between men and women, specific symptoms and national contexts, and focus on more chronic insomnia.
Asunto(s)
Sistema de Registros , Trastornos del Inicio y del Mantenimiento del Sueño/mortalidad , Trastornos del Inicio y del Mantenimiento del Sueño/fisiopatología , Adulto , Anciano , Causas de Muerte , Enfermedad Crónica/epidemiología , Estudios de Cohortes , Femenino , Finlandia/epidemiología , Humanos , Lituania/epidemiología , Masculino , Persona de Mediana Edad , Noruega/epidemiología , Modelos de Riesgos Proporcionales , Sueño , Trastornos del Inicio y del Mantenimiento del Sueño/epidemiología , VigiliaRESUMEN
BACKGROUND: Previous research suggests a possible link between insomnia and mortality, but findings are mixed and well-controlled studies are lacking. The aim of the current study was to examine the effect of insomnia in middle age on all-cause mortality. METHODS: Using a cohort design with 13-15 years follow-up, mortality registry data were linked to health information obtained during 1997-99, as part of the community-based Hordaland Health Study (HUSK), in Western Norway. 6,236 participants aged 40-45 provided baseline information on self- reported insomnia using the Karolinska Sleep Questionnaire Scale (defined according to the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-V), sociodemographic factors, health behaviors, shift/night-work, obstructive sleep apnea symptoms, sleep duration, sleep medication use, anxiety, depression, as well as a range of somatic diagnoses and symptoms. Height, weight and blood pressure were measured. Information on mortality was obtained from the Norwegian Cause of Death Registry. RESULTS: Insomnia was reported by 5.6% (349/6236) at baseline and a significant predictor of all-cause-mortality (hazard ratio [HR] = 2.74 [95% CI:1.75-4.30]). Adjusting for all confounders did not attenuate the effect (HR = 3.34 [95% CI:1.67-6.69]). Stratifying by gender, the effect was especially strong in men (HR = 4.72 [95% CI:2.48-9.03]); but also significant in women (adjusted HR = 1.96 [95% CI:1.04-3.67]). The mortality risk among participants with both insomnia and short sleep duration (<6.5 hours) was particularly high, whereas insomnia in combination with normal/greater sleep duration was not associated with mortality. CONCLUSIONS: Insomnia was associated with a three-fold risk of mortality over 13-15 years follow-up. The risk appeared even higher in males or when insomnia was combined with short sleep duration, although such unadjusted subgroup analyses should be interpreted with caution. Establishing prevention strategies and low-threshold interventions should consequently be a prioritized task for public health policy.
Asunto(s)
Trastornos del Inicio y del Mantenimiento del Sueño/mortalidad , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Noruega/epidemiología , Sistema de Registros , Medición de Riesgo , Trastornos del Inicio y del Mantenimiento del Sueño/tratamiento farmacológico , Trastornos del Inicio y del Mantenimiento del Sueño/psicología , Encuestas y CuestionariosRESUMEN
The circadian system develops and changes in a gradual and programmed process over the lifespan. Early in life, maternal care represents an important zeitgeber and thus contributes to the development of circadian rhythmicity. Exposure to early life stress may affect circadian processes and induce a latent circadian disturbance evident after exposure to later life stress. Disturbance of the normal regulation of circadian rhythmicity is surmised to be an etiological factor in depression. We used postnatal maternal separation in rats to investigate how the early life environment might modify the circadian response to later life unpredictable and chronic stress. During postnatal days 2-14, male Wistar rats (n = 8 per group) were daily separated from their mothers for a period of either 180 min (long maternal separation; LMS) or 10 min (brief maternal separation; BMS). In adulthood, rats were exposed to chronic mild stress (CMS) for 4 weeks. Body temperature, locomotor activity and heart rate were measured and compared before and after CMS exposure. LMS offspring showed a delayed body temperature acrophase compared to BMS offspring. Otherwise, adult LMS and BMS offspring demonstrated similar diurnal rhythms of body temperature, locomotor activity and heart rate. Exposure to CMS provoked a stronger and longer lasting hypothermia in LMS rats than in BMS rats. The thermoregulatory response appears to be moderated by maternal care following reunion, an observation made in the LMS group only. The results show that early life stress (LMS) in an early developmental stage induced a thermoregulatory disturbance evident upon exposure to unpredictable adult life stressors.
Asunto(s)
Ansiedad de Separación/complicaciones , Ritmo Circadiano , Hipotermia/etiología , Privación Materna , Estrés Psicológico/complicaciones , Factores de Edad , Animales , Animales Recién Nacidos , Ansiedad de Separación/sangre , Ansiedad de Separación/fisiopatología , Ansiedad de Separación/psicología , Conducta Animal , Biomarcadores/sangre , Regulación de la Temperatura Corporal , Enfermedad Crónica , Corticosterona/sangre , Modelos Animales de Enfermedad , Femenino , Frecuencia Cardíaca , Hipotermia/sangre , Hipotermia/fisiopatología , Hipotermia/psicología , Masculino , Actividad Motora , Ratas Wistar , Factores de Riesgo , Estrés Psicológico/sangre , Estrés Psicológico/fisiopatología , Estrés Psicológico/psicología , Factores de TiempoRESUMEN
Exposure to early life stress may profoundly influence the developing brain in lasting ways. Neuropsychiatric disorders associated with early life adversity may involve neural changes reflected in EEG power as a measure of brain activity and disturbed sleep. The main aim of the present study was for the first time to characterize possible changes in adult EEG power after postnatal maternal separation in rats. Furthermore, in the same animals, we investigated how EEG power and sleep architecture were affected after exposure to a chronic mild stress protocol. During postnatal day 2-14 male rats were exposed to either long maternal separation (180 min) or brief maternal separation (10 min). Long maternally separated offspring showed a sleep-wake nonspecific reduction in adult EEG power at the frontal EEG derivation compared to the brief maternally separated group. The quality of slow wave sleep differed as the long maternally separated group showed lower delta power in the frontal-frontal EEG and a slower reduction of the sleep pressure. Exposure to chronic mild stress led to a lower EEG power in both groups. Chronic exposure to mild stressors affected sleep differently in the two groups of maternal separation. Long maternally separated offspring showed more total sleep time, more episodes of rapid eye movement sleep and higher percentage of non-rapid eye movement episodes ending in rapid eye movement sleep compared to brief maternal separation. Chronic stress affected similarly other sleep parameters and flattened the sleep homeostasis curves in all offspring. The results confirm that early environmental conditions modulate the brain functioning in a long-lasting way.
Asunto(s)
Mapeo Encefálico , Encéfalo/fisiopatología , Sueño/fisiología , Estrés Psicológico/fisiopatología , Animales , Electroencefalografía , Homeostasis , Masculino , Privación Materna , Ratas , Ratas Wistar , Sueño REM/fisiología , Vigilia/fisiologíaRESUMEN
The aim of this study was to explore and compare the effect of noise from railway and road traffic on sleep in subjects habitually exposed to nocturnal noise. Forty young and middle aged healthy subjects were studied with polysomnography (PSG) during two consecutive nights in their own bedroom. Noise measurements and recordings were conducted concurrently outside of the bedroom façade as well as inside the bedroom of each participant. Different noise exposure parameters were calculated (L(p,A,eq,night), L(p,A,Fmax,night), and L(AF5,night)) and analyzed in relation to whole-night sleep parameters. The group exposed to railway noise had significantly less Rapid eye movement, (REM) sleep than the group exposed to road traffic noise. A significant association was found between the maximum level (L(p,A,Fmax,night)) of railway noise and time spent in REM sleep. REM sleep was significantly shorter in the group exposed to at least a single railway noise event above 50 dB inside the bedroom. These results, obtained in an ecological valid setting, support previous laboratory findings that railway noise has a stronger impact than road traffic noise on physiological parameters during sleep, and that the maximum noise level is an important predictor of noise effects on sleep assessed by PSG, at least for railway noise.
Asunto(s)
Automóviles , Ruido del Transporte/efectos adversos , Polisomnografía , Vías Férreas , Trastornos del Sueño-Vigilia/etiología , Sueño REM , Adulto , Exposición a Riesgos Ambientales , Monitoreo del Ambiente/métodos , Análisis Factorial , Femenino , Humanos , Masculino , Persona de Mediana Edad , Noruega , Medición de Riesgo , Factores de Riesgo , Trastornos del Sueño-Vigilia/diagnóstico , Trastornos del Sueño-Vigilia/fisiopatología , Espectrografía del Sonido , Factores de TiempoRESUMEN
BACKGROUND: Seasonal variations in mood and behaviour, termed seasonality, are commonly reported in the general population. As a part of a large cross-sectional health survey in Hordaland, Norway, we investigated the relationship between seasonality, objective health measurements and health behaviours. METHODOLOGY/PRINCIPAL FINDINGS: A total of 11,545 subjects between 40-44 years old participated, completing the Global Seasonality Score, measuring seasonality. Waist/hip circumference, BMI and blood pressure were measured, and blood samples were analyzed for total cholesterol, HDL cholesterol, triglycerides and glucose. Subjects also completed a questionnaire on miscellaneous health behaviours (exercise, smoking, alcohol consumption). Hierarchical linear regression analyses were used to investigate associations between seasonality and objective health measurements, while binary logistic regression was used for analysing associations between seasonality and health behaviours. Analyses were adjusted for sociodemographic factors, month of questionnaire completion and sleep duration. Seasonality was positively associated with high waist-hip-ratio, BMI, triglyceride levels, and in men high total cholesterol. Seasonality was negatively associated with HDL cholesterol. In women seasonality was negatively associated with prevalence of exercise and positively associated with daily cigarette smoking. CONCLUSIONS/SIGNIFICANCE: High seasonality was associated with objective health risk factors and in women also with health behaviours associated with an increased risk for cardiovascular disease.
Asunto(s)
Afecto , Conductas Relacionadas con la Salud , Estado de Salud , Estaciones del Año , Adulto , Colesterol/metabolismo , Ejercicio Físico , Femenino , Humanos , Masculino , Noruega , Riesgo , Factores Sexuales , Fumar , Encuestas y Cuestionarios , Triglicéridos/metabolismoRESUMEN
BACKGROUND: Sleep problems are a frequent cause for contacting primary care services. Knowledge of basic mechanisms behind sleep and wakefulness is essential for giving adequate information and correct patients' frequent misperception of sleep. MATERIAL AND METHODS: The present review is based on literature identified through a non-systematic search of Pub-med as well as the authors' own research experience. RESULTS: Sleep need (homeostatic factor), circadian rhythm and behaviour regulate sleepiness, sleep depth and sleep duration. Falling asleep requires central-nervous deactivation. Sleep depth depends on the length of wakefulness beforehand, while duration of sleep mainly depends on timing in relation to the circadian phase of activation. Activation and wakefulness are the combined result of activating several different parts of the brain: thalamus, the reticular activation system, basal forebrain, hypothalamus and monoaminergic cell groups in the brainstem. Falling asleep is a dynamic process and is primarily a consequence of behaviourally induced deactivation. Sleep is especially modulated by GABAergic neurons in the thalamus and basal forebrain, but several neurotransmitters and endogenous substances modulate sleep and wakefulness. Sleep and wakefulness are complex phenomena, and the activity in different brain regions is markedly different depending on whether you are awake or asleep. Hence, a manipulation of these, e.g. by use of certain medications, may cause sleep problems. INTERPRETATION: Knowledge of sleep is essential for adequate evaluation and treatment of sleep disturbances.
Asunto(s)
Trastornos del Sueño-Vigilia , Sueño , Estimulantes del Sistema Nervioso Central/farmacología , Ritmo Circadiano/fisiología , Homeostasis/efectos de los fármacos , Homeostasis/fisiología , Humanos , Transducción de Señal/efectos de los fármacos , Transducción de Señal/fisiología , Sueño/efectos de los fármacos , Sueño/fisiología , Trastornos del Sueño-Vigilia/tratamiento farmacológico , Trastornos del Sueño-Vigilia/fisiopatología , Sueño REM/fisiología , Vigilia/fisiologíaRESUMEN
OBJECTIVES: The aim of this study was to examine the relationship between occupation and sleep duration, sleepiness, insufficient sleep, and insomnia in day and shift workers (including night work and watches). METHODS: The study was population-based and cross-sectional, and relied on self-administered questionnaires. It was conducted as part of the 1997-1999 Hordaland Health Study in collaboration with the Norwegian National Health Screening Service. Aged 40-45 years, 7782 participants answered a sleep questionnaire, reporting their occupation and whether or not they were employed in shift work. RESULTS: Our study found differences in sleep duration during the working week between occupational groups; in both shift and day workers. Craft workers, plant operators, and drivers slept less than leaders, and non-personal and personal service workers. Within some occupations (leaders, personal service workers, and plant operators), shift workers slept less than day workers. The mean sleep duration of shift workers was 15 minutes shorter than that of day workers. Rise times, but not bedtimes, were earlier in craft-and construction workers, plant operators, and drivers than in leaders and non-personal and personal service workers, particularly day workers. When adjusted for shift work and working hours - compared to leaders - craft workers, plant operators, and drivers had an increased risk of daytime sleepiness (odds ratio 1.5, 1.8, and 1.8 respectively) and of falling asleep at work (odds ratio 1.6, 2.1 and 2.0 respectively). Shift workers had an increased risk of falling asleep at work and insomnia. CONCLUSIONS: Occupation has separate effects on sleep duration and sleep-related problems, independent of the effects of shift work.
Asunto(s)
Ocupaciones , Trastornos del Sueño-Vigilia/epidemiología , Sueño/fisiología , Adulto , Análisis de Varianza , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Noruega/epidemiología , Salud Laboral , Vigilancia de la Población , Encuestas y Cuestionarios , Tolerancia al Trabajo ProgramadoRESUMEN
Social defeat, resulting from the fight for a territory is based on the resident-intruder paradigm. A male rat intruder is placed in the territory of an older, bigger and more aggressive male resident and is defeated. In the present study, a double exposure to social defeat increased sleep fragmentation due to an increased amount of waking and slow-wave-sleep-1 (SWS-1) episodes. Also, social defeat increased the amount of slow-wave-sleep-2 (SWS-2). In repeated exposures to an open field, socially defeated rats showed low central activity and persistent defecation indicating high emotionality. The strongest effects of social defeat on sleep and open field behaviour were seen sub-chronically after stress. Social defeat did not induce changes in rapid eye movement (REM) sleep (e.g. total amount, latency), sleep latency, sexual activity, body weight or adrenal weight. A negative correlation between habituation in open field central activity and total sleep fragmentation indicates a commonality of effects of social defeat on both behaviour and sleep.
Asunto(s)
Agresión/psicología , Actividad Motora/fisiología , Sueño/fisiología , Conducta Social , Estrés Fisiológico/fisiología , Glándulas Suprarrenales/anatomía & histología , Conducta Agonística/fisiología , Animales , Peso Corporal/fisiología , Conducta Exploratoria/fisiología , Masculino , Ratas , Ratas Wistar , Tiempo de Reacción/fisiología , Privación de Sueño/fisiopatología , Privación de Sueño/psicología , Fases del Sueño/fisiología , Sueño REM/fisiología , Vigilia/fisiologíaRESUMEN
Change in sleep duration dependent on time of year is a central characteristic of seasonal affective disorder (SAD). In a community health survey, we analysed associations between seasonality, subjective sleep problems and sleep duration. Totally, 8860 subjects (3531 men and 5329 women) aged between 40 and 44 years were included in the study. Seasonal changes in mood and behaviour were measured by the Global Seasonality Score (GSS) questionnaire, and subjects were grouped in high (GSS > or = 11), moderate (GSS 8-10) or low (GSS < 8) seasonality groups. Sleep symptomatology was assessed using a modified version of the Karolinska Sleep Questionnaire. Significant sleep duration deficiency was defined as the difference between subjective sleep need and sleep duration of at least 1 h. Sleep problems suggesting insomnia as well as increased daytime sleepiness were more prevalent in the high/moderate seasonality groups compared with the low seasonality group. Seasonality was furthermore associated with shorter sleep duration and increased subjective sleep need. Significant sleep duration deficiency was more prevalent in subjects reporting high (men 20% and women 21%) and moderate (men 13% and women 19%) seasonality than subjects reporting low (men 10% and women 14%) seasonality. In conclusion, we found seasonal changes in mood and behaviour to be associated with several sleep-related complaints. Sleep duration deficiency increased with increasing seasonality, mainly due to increasing subjective sleep need.
Asunto(s)
Estaciones del Año , Privación de Sueño/diagnóstico , Privación de Sueño/epidemiología , Trastornos del Sueño-Vigilia/diagnóstico , Trastornos del Sueño-Vigilia/epidemiología , Adulto , Femenino , Humanos , Masculino , Prevalencia , Índice de Severidad de la Enfermedad , Encuestas y Cuestionarios , Factores de TiempoRESUMEN
Previous studies have suggested that memory is dependent on the occurrence of REM sleep. Research has mainly focused on two distinct types of memory function, declarative and procedural, and it seems that the latter may more directly depend on REM sleep. Memory consolidation has been more investigated than acquisition, maintenance, and recall, despite the fact that sleep may affect flow of information into/from storage. Moreover, tests have often been limited to stimuli within only one modality (usually visual or verbal). This study aimed to clarify the role of REM sleep in memory by investigating aspects of memory function, processing, and modality in the same experimental setting. Tests of acquisition and consolidation of multiple aspects of memory function within the visual and verbal modalities were administrated to subjects before and after REM sleep deprivation. Results show that test performance was not affected by REM sleep deprivation.
Asunto(s)
Memoria/fisiología , Privación de Sueño/psicología , Sueño REM/fisiología , Adulto , Femenino , Humanos , Masculino , Recuerdo Mental/fisiología , Pruebas Neuropsicológicas , Polisomnografía , Desempeño Psicomotor/fisiologíaRESUMEN
One of the most established hypotheses of depression focuses on alteration of the serotonergic (5-HT) function. Recent evidence suggests that serotonergic involvement in depression may be modulated by the action of gamma-hydroxybutyric acid (GABA). Furthermore, altered GABAergic function is also evident in depressed patients and in animal models of depression. Disturbed sleep is characteristic of patients with mood disorders. The most pronounced changes of the 5-HT firing activity occur during sleep. Hence, the present paper reports a study on simultaneously measurement of hippocampal levels of serotonin and GABA during waking and sleep in the chronic mild stress (CMS) animal model of depression. The neurotransmitter findings are accompanied by depression-like symptoms (e.g. sleep alterations and reduced sucrose intake, a putative indicator of anhedonia in rodents). Our results show that animals exposed to CMS had lower hippocampal GABA levels compared to controls. In addition, after CMS there was a lack of 5-HT stage-dependency. A subgroup (five out of eight animals) showed a consistent increase in 5-HT levels in slow wave sleep and REM sleep. We also observed that this increase occurred in those animals regarded as most anhedonic (lowest intake of sucrose solution). Moreover, REM sleep was positively correlated with anhedonia. No interaction between 5-HT and GABA was found in the hippocampus. The data suggest that both GABAergic and serotonergic systems may be simultaneously but independently involved in depression. The alteration in 5-HT function may represent a link between depression-like behaviour and sleep abnormalities found in depressed patients.
Asunto(s)
Depresión , Líquido Extracelular/metabolismo , Hipocampo/metabolismo , Serotonina/metabolismo , Estrés Psicológico/patología , Ácido gamma-Aminobutírico/metabolismo , Análisis de Varianza , Animales , Conducta Animal , Cromatografía Líquida de Alta Presión/métodos , Depresión/metabolismo , Depresión/fisiopatología , Modelos Animales de Enfermedad , Masculino , Microdiálisis/métodos , Ratas , Ratas Sprague-Dawley , Tiempo de Reacción/fisiología , Sueño/fisiología , Estrés Psicológico/fisiopatología , Caminata/fisiologíaRESUMEN
Several studies show that short self-reported sleep duration is associated with elevated body mass index (BMI). Short sleep duration may change appetite hormones, but whether this also influences metabolic measures like cholesterol and triglycerides is less clear. Furthermore, obesity is linked to increases in blood pressure, and recently, short sleep duration has been shown to be an independent risk factor for hypertension. This is a population-based cross-sectional study (The Hordaland Health Study). A subgroup of 8860 subjects, aged 40-45 years, answered a sleep questionnaire. Body weight, height and blood pressure were measured, and non-fasting blood samples were collected and analyzed for total cholesterol, HDL-cholesterol and triglycerides. Sleep duration was divided into the following subgroups: < 5, 5-5.99, 6-6.99, 7-7.99, 8-8.99 and > or = 9 h. The results show that short sleep duration was associated with elevated BMI and increased prevalence of obesity. Similar to BMI, levels of cholesterol, triglycerides, systolic and diastolic blood pressure were higher in subjects with short sleep duration. This co-variation seemed to be attributed to variables like gender, smoking and BMI. In conclusion, our study confirms a clear association between short sleep duration and elevated BMI and obesity. Furthermore, levels of total cholesterol, HDL-cholesterol, triglycerides and blood pressure were associated with sleep duration.
Asunto(s)
Metabolismo Basal/fisiología , Estado de Salud , Sueño/fisiología , Tejido Adiposo/metabolismo , Adulto , Presión Sanguínea/fisiología , Índice de Masa Corporal , HDL-Colesterol/metabolismo , Estudios Transversales , Femenino , Humanos , Hipercolesterolemia/epidemiología , Masculino , Obesidad/epidemiología , Obesidad/metabolismo , Prevalencia , Encuestas y Cuestionarios , Factores de Tiempo , Triglicéridos/metabolismoRESUMEN
We investigated the effects of the perfusion of gamma-aminobutyric acid(A) antagonist bicuculline in the dorsal raphe nucleus, on brain 5-hydroxytryptamine level and on sleep. Perfusion of 25 and 50 microM bicuculline into the dorsal raphe nucleus dose-dependently increased dorsal raphe nucleus 5-hydroxytryptamine level during sleep and wakefulness. Frontal cortex 5-hydroxytryptamine level was not affected by either 25 or 50 microM perfusion. 25 microM bicuculline produced only minimal effects on sleep. 50 microM decreased rapid eye movement sleep, slow wave sleep 1 and 2 and increased waking. Sleep changes leveled out towards the end of the bicuculline perfusion despite serotonin levels were still elevated. This suggests that an adaptation mechanism may take place in order to counteract the high serotonergic output, producing uncoupling between serotonin level and behavioural state. The results support the notion that gamma-aminobutyric acid is a strong modulator of dorsal raphe nucleus serotonergic neurons, and that this modulation is important in the regulation of slow wave sleep, rapid eye movement sleep and waking.
Asunto(s)
Bicuculina/farmacología , Lóbulo Frontal/efectos de los fármacos , Antagonistas de Receptores de GABA-A , Núcleos del Rafe/efectos de los fármacos , Serotonina/metabolismo , Sueño REM , Animales , Cromatografía Líquida de Alta Presión , Electroencefalografía , Lóbulo Frontal/metabolismo , Masculino , Núcleos del Rafe/metabolismo , Núcleos del Rafe/fisiología , Ratas , Ratas Sprague-DawleyRESUMEN
Chronic stress is linked to development of depression and may trigger neurobiological changes underlying the disease. Downregulation of the secretory peptide brain-derived neurotrophic factor (BDNF) and the transcriptional regulator calcium/cyclic-AMP responsive binding protein (CREB) have been implicated in stress and depression-related pathology in animal studies. When animals are exposed to the chronic mild stress (CMS) protocol, multiple depression-like symptoms are observed. Here we investigated the effect of CMS on BDNF protein expression and CREB activation in the dentate gyrus and hippocampus proper. Rats exposed for 5 weeks to repeated, unpredictable, mild stressors showed reduced BDNF expression and inhibited phosphorylation of CREB (Ser-133) in the dentate gyrus (-25.0%+/-3.5% and -29.7+/-7.3%, respectively), whereas no significant effects were observed in the hippocampus proper. CMS-treated rats consumed less sucrose compared to control rats, indicating a state of anhedonia. Moreover, phospho-CREB levels in the dentate gyrus were positively correlated with the animals' sucrose intake at the end of the CMS protocol. These results couple chronic mild stress to a downregulation of CREB activity and BDNF protein expression specifically within the dentate gyrus and support the possibility that the BDNF-CREB system plays an important role in the response to environmental challenges.
Asunto(s)
Factor Neurotrófico Derivado del Encéfalo/biosíntesis , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Giro Dentado/metabolismo , Hipocampo/metabolismo , Estrés Psicológico/metabolismo , Animales , Regulación del Apetito , Enfermedad Crónica , Masculino , Fosforilación , Ratas , Ratas Sprague-Dawley , Sacarosa/metabolismoRESUMEN
OBJECTIVE: To explore the relationship between demographic factors and seasonal changes in mood and behaviour. METHOD: A health survey was conducted among 40-45 year old inhabitants in Hordaland County, Norway. The Global Seasonality Score, investigating seasonal symptoms, was given to 4299 men and 9983 women. Response rates among those receiving the questionnaire were 79.8% for men (n = 3432) and 81.2% for women (n = 8223). RESULTS: High seasonality was reported by 18.4% of men and 22.2% of women. Female gender, low educational level, high level of affective symptomatology and low household income correlated with high seasonality. Among men, being single was also a determinant factor for high seasonality. Reported seasonality also depended on which month the questionnaire was filled in. CONCLUSIONS: In this study, high seasonality was most prevalent among females, being single, having a low annual income and a low education level. The latter two findings are different from expectations which could be drawn from previous studies suggesting an opposite association.
Asunto(s)
Afecto , Conducta , Estaciones del Año , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Noruega/epidemiología , Trastorno Afectivo Estacional/epidemiología , Factores Sexuales , Factores SocioeconómicosRESUMEN
STUDY OBJECTIVE: To report the distribution of various sleep parameters in a population-based study. DESIGN: Population-based cross-sectional study with self-administered questionnaires. SETTING: Conducted as part of the Hordaland Health Study '97-'99 in collaboration with the Norwegian National Health Screening Service. PARTICIPANTS: 8860 subjects, aged 40 to 45 years, answered the sleep questionnaire part of the study. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Reports on habitual bedtimes, rise times, subjective sleep need, and various sleep characteristics were used in this study. Mean (+/- SD) nocturnal sleep duration during weekdays in men was 6 hours 52 minutes (+/- 55 minutes); in women 7 hours 11 minutes (+/- 57 minutes). Mean subjective sleep need was 7 hours 16 minutes (+/- 52 minutes) in men; 7 hours 45 minutes (+/- 52 minutes) in women. Sleep duration was shorter in shift workers and longer in married subjects and in those living in rural areas. Subjective sleep need was higher in subjects reporting poor subjective health and in subjects living in rural areas. In total, these variables accounted for only around 3% of the variance in sleep duration and sleep need. Ten percent of the men and 12.2% of the women reported frequent insomnia. CONCLUSIONS: The wide distribution of sleep duration and subjective sleep need indicate large interindividual variations in these parameters. There were pronounced sex differences in these variables and in most of the sleep characteristics studied. Shift work, urban-rural living, marital status, and education in men were sources of significant, but small, variations in sleep duration.
Asunto(s)
Actitud Frente a la Salud , Hábitos , Sueño , Adulto , Estudios Transversales , Femenino , Estado de Salud , Humanos , Masculino , Persona de Mediana Edad , Vigilancia de la Población , Trastornos del Sueño del Ritmo Circadiano/diagnóstico , Trastornos del Sueño del Ritmo Circadiano/epidemiología , Fases del Sueño , Encuestas y Cuestionarios , Factores de TiempoRESUMEN
Many symptoms of human depressive disorders are also observed in animals after exposure to unpredictable stressors. The chronic mild stress (CMS) paradigm was developed in order to better model the human situation by using chronic mild stressors over a longer period. It is claimed that the model induces anhedonia in the animals, a core symptom of depression in humans. Despite the fact that the CMS model has a high degree of face validity, there are a number of laboratories in which the establishment of the model is less reliably observed. We have examined behavior (sexual activity and open field activity) together with hedonic measures (sucrose and saccharine intake) after exposure to CMS. CMS decreased male sexual activity (e.g. reduced capability to ejaculate) and increased activity in an open field test. The hedonic measures showed diverging results after CMS in our laboratory. Sucrose consumption was reduced, while saccharine consumption did not show a comparable change. It is concluded that CMS induces comparable alterations to some depression-like symptoms in humans. Saccharine consumption is not a reliable indicator of the hedonic responsiveness to CMS.
Asunto(s)
Depresión/psicología , Preferencias Alimentarias/psicología , Actividad Motora/fisiología , Conducta Sexual Animal/fisiología , Estrés Psicológico/fisiopatología , Estrés Psicológico/psicología , Análisis de Varianza , Animales , Enfermedad Crónica , Depresión/etiología , Depresión/fisiopatología , Modelos Animales de Enfermedad , Conducta de Ingestión de Líquido/fisiología , Conducta Exploratoria/fisiología , Femenino , Preferencias Alimentarias/fisiología , Masculino , Ratas , Ratas Sprague-Dawley , Recompensa , Sacarina , Estrés Psicológico/complicaciones , Sacarosa , Gusto/fisiologíaRESUMEN
Depression in humans is associated with sleep abnormalities of three types: altered rapid eye movement (REM) sleep, fragmented sleep, and reduced delta sleep. In an animal model of depression, chronic exposure to mild stressors (CMS, e.g. periods of soiled cage, reversed light/dark cycle, grouped housing, food and/or water deprivation) causes behavioral and hormonal changes which, in humans, often are associated with depression. In the CMS model, a reduced sucrose intake has been defined as one of the core symptoms of depression, anhedonia, although this finding is not consistent among various laboratories. In the present study, we investigated if the CMS procedure, in our laboratory, would cause decreased sucrose intake and, also, give sleep changes similar to what is found in depressed patients. Exposure to CMS decreased sucrose intake in our rats. The largest effect was obtained after 2 weeks of the stress protocol. CMS rats spent more time in REM sleep and showed more fragmented sleep compared to their baseline recording, while there were no changes in the control rats. Increased sleep fragmentation in CMS rats was particularly evident by increased number of arousals, and increased REM sleep and slow-wave-sleep-1 (SWS-1) episodes. The duration of sleep stage episodes was decreased. The amount of slow-wave-sleep-2 (SWS-2) was not decreased, however SWS-2 in percent of total SWS was reduced. Correlation analysis showed that animals that had less consumption of sucrose spent more time in REM sleep and had increased number of REM sleep episodes. In this study, CMS appears to be a model of depression.
Asunto(s)
Ingestión de Alimentos/fisiología , Sueño/fisiología , Estrés Psicológico/psicología , Animales , Peso Corporal , Corticosterona/sangre , Electroencefalografía , Electromiografía , Sistema Hipotálamo-Hipofisario/fisiología , Masculino , Sistema Hipófiso-Suprarrenal/fisiología , Ratas , Ratas Sprague-Dawley , Fases del Sueño/fisiología , Sueño REM/fisiología , SacarosaRESUMEN
For 50 years, serotonin has been in the centre of the search for the mechanisms and control of sleep. Serotonergic neurotransmission is related to the behavioural state of the animal and plays an important role in modulation of the behavioural state, by interacting with other brain areas modulating circadian rhythm, sleep and waking. Serotonergic activity may be accompanied by waking or sleep depending on the brain area and receptor type involved in the response, on the current behavioural state and on the concomitant agonism/antagonism of other neurotransmitter systems.