Sleep regulatory factors.

The state of sleep consists of different phases that proceed in successive, tightly regulated order through the night forming a physiological program, which for each individual is different but stabile from one night to another. Failure to accomplish this program results in feeling of unrefreshing sleep and tiredness in the morning. The pro- gram core is constructed by genetic factors but regulated by circadian rhythm and duration and intensity of day time brain activity. Many environmental factors modulate sleep, including stress, health status and ingestion of vigilance-affecting nutrients or medicines (e.g. caffeine). Knowledge of the factors that regulate the spontaneous sleep-wake cycle and factors that can affect this regulation forms the basis for diagnosis and treatment of the many common disorders of sleep.

Adenosine: a mediator of the sleep-inducing effects of prolonged wakefulness.

Both subjective and electroencephalographic arousal diminish as a function of the duration of prior wakefulness. Data reported here suggest that the major criteria for a neural sleep factor mediating the somnogenic effects of prolonged wakefulness are satisfied by adenosine, a neuromodulator whose extracellular concentration increases with brain metabolism and which, in vitro, inhibits basal forebrain cholinergic neurons. In vivo microdialysis measurements in freely behaving cats showed that adenosine extracellular concentrations in the basal forebrain cholinergic region increased during spontaneous wakefulness as contrasted with slow wave sleep; exhibited progressive increases during sustained, prolonged wakefulness; and declined slowly during recovery sleep. Furthermore, the sleep-wakefulness profile occurring after prolonged wakefulness was mimicked by increased extracellular adenosine induced by microdialysis perfusion of an adenosine transport inhibitor in the cholinergic basal forebrain but not by perfusion in a control noncholinergic region.

Association of depressive symptoms and metabolic syndrome in men.

OBJECTIVE: To explore the relationship between several indicators of depression and metabolic syndrome (MetS). METHOD: A population-based sample with high (HMS group) or low (LMS group) levels of mental symptoms, including those of depression, in three follow-ups participated in a clinical examination in 2005 (n = 223). MetS was determined according to the NCEP criteria. RESULTS: The prevalence of MetS was 49% in men and 21% in women. Men with MetS had higher rates of major depressive disorder than other men. They also displayed higher Hamilton Rating Scale for Depression (HDRS) scores and more often signs of suicidality. In logistic regression analyses, higher HDRS scores (OR 1.31, 95% CI 1.04-1.64) and belonging to the HMS group (OR 10.1, 95% CI 1.98-51.3) were independent associates for MetS but only in men. CONCLUSION: The results highlight that there is an association between long-term depressive symptoms and the emergence of MetS, especially in men.

Recurrent groin hernia surgery after primary open inguinal procedures: a reappraisal of the open preperitoneal (Ugahary) technique.

PURPOSE: There are several methods for repairing recurrent inguinal hernia, depending on the type of initial repair. Our aim was to analyze our long follow-up results on the open preperitoneal repair for patients with recurrent inguinal hernia. METHODS: Our retrospective survey included 135 consecutive recurrent inguinal hernia patients, operated on during 1999-2010, with a mean follow-up time of 8.7 years. RESULTS: During the mean follow-up time of 8.7 years, only four (3%) patients developed a re-recurrence. Two of these patients were asymptomatic, and the two other were operated on. Early postoperative complications occurred in four (3%) patients. The complications comprised one hematoma, one seroma, and two infections. Chronic pain was diagnosed in five (3.7%) patients, but their symptoms disappeared spontaneously within a few years. CONCLUSIONS: We conclude that in competent hands, the open preperitoneal repair (Ugahary) is a good surgical option in operating recurrent inguinal hernias.

The role of cholinergic basal forebrain neurons in adenosine-mediated homeostatic control of sleep: lessons from 192 IgG-saporin lesions.

A topic of high current interest and controversy is the basis of the homeostatic sleep response, the increase in non-rapid-eye-movement (NREM) sleep and NREM-delta activity following sleep deprivation (SD). Adenosine, which accumulates in the cholinergic basal forebrain (BF) during SD, has been proposed as one of the important homeostatic sleep factors. It is suggested that sleep-inducing effects of adenosine are mediated by inhibiting the wake-active neurons of the BF, including cholinergic neurons. Here we examined the association between SD-induced adenosine release, the homeostatic sleep response and the survival of cholinergic neurons in the BF after injections of the immunotoxin 192 immunoglobulin G (IgG)-saporin (saporin) in rats. We correlated SD-induced adenosine level in the BF and the homeostatic sleep response with the cholinergic cell loss 2 weeks after local saporin injections into the BF, as well as 2 and 3 weeks after i.c.v. saporin injections. Two weeks after local saporin injection there was an 88% cholinergic cell loss, coupled with nearly complete abolition of the SD-induced adenosine increase in the BF, the homeostatic sleep response, and the sleep-inducing effects of BF adenosine infusion. Two weeks after i.c.v. saporin injection there was a 59% cholinergic cell loss, correlated with significant increase in SD-induced adenosine level in the BF and an intact sleep response. Three weeks after i.c.v. saporin injection there was an 87% cholinergic cell loss, nearly complete abolition of the SD-induced adenosine increase in the BF and the homeostatic response, implying that the time course of i.c.v. saporin lesions is a key variable in interpreting experimental results. Taken together, these results strongly suggest that cholinergic neurons in the BF are important for the SD-induced increase in adenosine as well as for its sleep-inducing effects and play a major, although not exclusive, role in sleep homeostasis.

Itraconazole, a potent inhibitor of P-glycoprotein, moderately increases plasma concentrations of oral morphine.

BACKGROUND: Individual variation in opioid response is considerable, partly due to pharmacokinetic factors. Transporter proteins are becoming increasingly interesting also in the pharmacokinetics of opioids. The efflux transporter P-glycoprotein can affect gastrointestinal absorption and tissue distribution, particularly brain access of many opioids. The aim of this study was to evaluate whether itraconazole, which is a potent inhibitor of P-glycoprotein and CYP3A4, would change the pharmacokinetics or the pharmacodynamics of oral morphine. METHODS: Twelve healthy male volunteers ingested, in a randomized crossover study, once daily 200 mg itraconazole or placebo for 4 days. On day 4, 1 h after the last pre-treatment dose, the subjects ingested 0.3 mg/kg morphine. Blood samples for the determination of plasma morphine, morphine-3-glucuronide (M3G), morphine-6-glucuronide (M6G) and itraconazole concentrations were drawn up to 48 h after morphine ingestion. Pharmacodynamic effects were evaluated using a questionnaire, visual analogue scales, a reaction time test, the Digit Symbol Substitution Test and the Critical Flicker Fusion Test. RESULTS: Itraconazole increased the mean area under the plasma concentration-time curve [AUC (0-9)] of morphine by 29% (P=0.002), its AUC (0-48) by 22% (P=0.013) and its peak plasma concentration by 28% (P=0.035). Itraconazole did not significantly affect the pharmacokinetic variables of M3G or M6G or the pharmacodynamic effects of morphine. CONCLUSIONS: Itraconazole moderately increases plasma concentrations of oral morphine, probably by enhancing its absorption by inhibiting intestinal wall P-glycoprotein. A possible improvement of morphine penetration to the brain could not be observed.

Novel concepts in sleep regulation.

Knowledge regarding the cellular mechanisms of sleep regulation is accumulating rapidly. In addition to neurones, also non-neuronal brain cells (astrocytes and microglia) are emerging as potential players. New techniques, particularly optogenetics and designed receptors activated by artificial ligands (DREADD), have provided also sleep research with important additional tools to study the effect of either silencing or activating specific neuronal groups/neuronal networks by opening or shutting ion channels on cells. The advantages of these strategies are the possibility to genetically target specific cell populations and the possibility to either activate or inhibit them with inducing light signal into the brain. Studies probing circuits of NREM and REM sleep regulation, as well as their role in memory consolidation, have been conducted recently. In addition, fundamentally new thoughts and potential mechanisms have been introduced to the field. The role of non-neuronal tissues in the regulation of many brain functions has become evident. These non-neuronal cells, particularly astrocytes, integrate large number of neurones, and it has been suggested that one of their functions is to integrate the (neural) activity in larger brain areas-a feature that is one of the prominent features of also the state of sleep.

Glutamatergic stimulation of the basal forebrain elevates extracellular adenosine and increases the subsequent sleep.

A prolonged period of waking accumulates sleep pressure, increasing both the duration and the intensity of the subsequent sleep period. Delta power, which is calculated from the slow range electroencephalographic (EEG) oscillations (0.1-4 Hz), is regarded as the marker of sleep intensity. Recent findings indicate that not only the duration but also the quality of waking, determines the level of increase in the delta activity during the subsequent sleep period. Elevated levels of extracellular adenosine in the basal forebrain (BF) during prolonged waking have been proposed to act as the molecular signal of increased sleep pressure, but the role of BF neuronal activity in elevating adenosine has not been previously explored. We hypothesized that an increase in neuronal discharge in the BF would lead to increase in the extracellular adenosine and contribute to the increase in the subsequent sleep. To experimentally increase neuronal activity in the rat BF, we used 3 h in vivo microdialysis application of glutamate or its receptor agonists N-methyl-D-aspartate (NMDA) or AMPA. Samples for adenosine measurement were collected during the drug application and the EEG was recorded during and after the treatment, altogether for 24 h. All treatments increased the duration of the subsequent sleep following the application. In contrast, delta power was elevated only if both the waking EEG theta (5-9 Hz) power (which can be regarded as a marker of active waking) and the extracellular adenosine in the BF were increased during the application. These results indicate that increased neuronal activity in the BF, and particularly the type of neuronal activity coinciding with active waking, is one of the factors contributing to the buildup of the sleep pressure.

Twenty-four-hour rhythms in relation to the natural photoperiod: a field study in humans.

The daily rhythms of salivary melatonin, salivary cortisol, and axillary body temperature were measured in nine healthy volunteers in midsummer, around the autumn equinox, and in midwinter, at a latitude of 60 degrees N. The aim was to find out whether these rhythms were dependent on variations of the natural daylength. The samples were collected every 2 hr during 24-hr periods in everyday conditions. The individual rhythms were characterized with the acrophase estimates of the best-fitting cosine curve models and with the half-rise and half-decline times calculated from the raw data. The melatonin and cortisol rhythms were delayed significantly (about 1 hr) in midwinter as compared with summer and autumn. The most advanced rhythms were found in autumn. The shifts of the melatonin and cortisol rhythms could be explained as a result of the changes of natural illumination. The overt temperature rhythms did not differ significantly among the sampling months. The lack of seasonal patterns in temperature rhythms probably primarily reflected the socially determined rest-activity cycles of the subjects.

Neonatal hypothyroidism permanently alters follicle-stimulating hormone and luteinizing hormone production in the male rat.

Transient neonatal hypothyroidism, induced with the goitrogen 6-n-propyl-2-thiouracil (PTU), results in dramatic increases in both testis size and sperm production in the adult rat. The observed increases in testis size and function occur in the presence of normal circulating testosterone levels. However, circulating gonadotropin levels are chronically reduced by 30-50% at all times in treated males. To better understand the permanent reduction in serum gonadotropin levels following transient neonatal hypothyroidism, we conducted a series of experiments to evaluate pituitary and hypothalamic function in the adult male PTU-treated rat. PTU treatment led to a significant reduction in GnRH-stimulated LH production. Castration resulted in 3.9- to 8.5-fold increases in circulating gonadotropin levels in both treated and control males; however, the absolute increases were significantly reduced in treated males. In contrast to circulating levels, pituitary gonadotropin contents did not increase in treated males after castration. PTU treatment did not lead to a reduction in the density of either luteotropes or folliculotropes, and both cell types increased in size and density after castration. The relative concentrations of both gonadotropin beta-subunit messenger RNAs increased more slowly in treated males than in controls after castration. Thus, although treated rats have the intrinsic ability to produce normal circulating levels of LH and FSH, gonadal feedback and an overall reduction in gonadotrope synthetic ability combine to produce the chronically reduced circulating levels of these hormones.

Effects of blocking CYP2D6 on the pharmacokinetics and pharmacodynamics of oxycodone.

BACKGROUND: Oxycodone is metabolized in the liver by means of O-demethylation to form oxymorphone in a reaction catalyzed by the enzyme cytochrome P450 2D6 (CYP2D6). This enzyme is expressed as 2 phenotypes (extensive and poor metabolizers). Several drugs are metabolized by CYP2D6, and clinically relevant drug interactions may occur. The aim of this study was to evaluate the role of oxymorphone in mediating the opioid effects of oxycodone by means of blocking CYP2D6 with quinidine. METHODS: Ten healthy extensive metabolizers were administered 20 mg controlled-release oxycodone after premedication with placebo or 200 mg quinidine in this randomized, double-blind crossover study. A dose of 100 mg quinidine was administered 6 hours later. Plasma opioid concentrations, subjective pharmacodynamic ratings, and psychomotor function were assessed for 24 hours after drug administration. RESULTS: No oxymorphone was detected at any time after quinidine premedication in 8 of 10 subjects. Plasma oxycodone (difference not significant) and noroxycodone (P < .01) concentrations were greater after quinidine pretreatment. Prevention of the production of oxymorphone by quinidine did not affect the psychomotor or subjective drug effects of oxycodone. No difference in number of adverse effects was observed after the 2 pretreatments. CONCLUSIONS: A significant reduction in plasma oxymorphone levels did not substantially alter the pharmacodynamic effects of oxycodone. Analgesia was not evaluated because pain was not present.

Controlled-release oxycodone and morphine in cancer related pain.

Controlled-release (CR) formulations of oxycodone and morphine were compared in 45 patients with chronic cancer pain. The study was started with an open-label, randomised titration phase to achieve stable pain control for at least 48 h, followed by a double-blind, randomised, crossover phase in two periods, 3-6 days each. To blind the study using available tablet strengths, the dose ratio of oxycodone to morphine was set at 2:3. A daily telephone contact was maintained between the patient and the investigator. The patients were asked to assess pain intensity four times a day and acceptability of therapy twice daily, and to record possible adverse effects. Pharmacodynamic evaluations were performed at the end of each double-blind period. The patients were allowed to use escape analgesic (respective opioid as oral solution) as needed. Twenty-seven patients were evaluable for both safety and efficacy. Pain was well-controlled during both stable phases. When the period effect was taken into account the two opioids provided comparable analgesia. If the results of the two periods were combined, the patients consumed significantly more escape doses and the mean pain intensities were significantly greater with CR oxycodone. The total opioid consumption ratio of oxycodone to morphine was 2:3 when oxycodone was administered first, and 3:4 when oxycodone was administered after morphine. The total incidence of adverse experiences reported by the patients was similar, but significantly more vomiting occurred with morphine, whereas constipation was more common with oxycodone.

Epidural and subcutaneous morphine in the management of cancer pain: a double-blind cross-over study.

Ten patients who suffered from severe cancer-related pain participated in a randomised, double-blind and cross-over study to compare the effectiveness and acceptability of epidural and subcutaneous administration of morphine. The patients titrated themselves pain-free in 48 h using a patient controlled analgesia system. The median daily doses calculated from the consumption of the last 4-h study period were 372 mg for subcutaneous and 106 mg for epidural administration. The two modes of morphine administration turned out to be comparable in terms of both effectiveness and acceptability. Both treatments provided better pain relief with less adverse effects compared with the prestudy oral morphine treatment.

Brain site-specificity of extracellular adenosine concentration changes during sleep deprivation and spontaneous sleep: an in vivo microdialysis study.

Previous data suggested that increases in extracellular adenosine in the basal forebrain mediated the sleep-inducing effects of prolonged wakefulness. The present study sought to determine if the state-related changes found in basal forebrain adenosine levels occurred uniformly throughout the brain. In vivo microdialysis sample collection coupled to microbore high-performance liquid chromatography measured extracellular adenosine levels in six brain regions of the cat: basal forebrain, cerebral cortex, thalamus, preoptic area of hypothalamus, dorsal raphe nucleus and pedunculopontine tegmental nucleus. In all these brain regions extracellular adenosine levels showed a similar decline of 15 to 20% during episodes of spontaneous sleep relative to wakefulness. Adenosine levels during non-rapid eye movement sleep did not differ from rapid eye movement sleep. In the course of 6h of sleep deprivation, adenosine levels increased significantly in the cholinergic region of the basal forebrain (to 140% of baseline) and, to a lesser extent in the cortex, but not in the other regions. Following sleep deprivation, basal forebrain adenosine levels declined very slowly, remaining significantly elevated throughout a 3-h period of recovery sleep, but elsewhere levels were either similar to, or lower than, baseline. The site-specific accumulation of adenosine during sleep deprivation suggests a differential regulation of adenosine levels by as yet unidentified mechanisms. Moreover, the unique pattern of sleep-related changes in basal forebrain adenosine level lends strong support to the hypothesis that the sleep-promoting effects of adenosine, as well as the sleepiness associated with prolonged wakefulness, are both mediated by adenosinergic inhibition of a cortically projecting basal forebrain arousal system.

Adenosine, prolonged wakefulness, and A1-activated NF-kappaB DNA binding in the basal forebrain of the rat.

There is considerable evidence to suggest that adenosine is a modulator of behavioral state. Our previous reports showed that perfusion of adenosine into the basal forebrain decreased wakefulness. Furthermore, prolonged wakefulness resulted in increased levels of extracellular adenosine in the basal forebrain of cats and rats. However, the longer-term consequences of prolonged wakefulness and increased adenosine are largely unknown. We report here an increase in the DNA binding activity of the transcription factor, nuclear factor-kappa B (NF-kappaB) following 3 h of sustained wakefulness in the rat basal forebrain. Moreover, this treatment led to the appearance of the p65 subunit of NF-kappaB in the nucleus, as determined by western blot analysis of nuclear proteins. This contrasted with undetectable levels in the sleeping controls. A concomitant disappearance of I-kappaB in cytoplasm suggested the degradation of this inhibitor of NF-kappaB. In the acute in vitro basal forebrain slice preparation, perfusion of adenosine increased NF-kappaB DNA binding while pretreatment of the slices with the A1 adenosine receptor antagonist, cyclopentyl-1-3-dimethylxanthine, significantly reduced NF-kappaB DNA binding. These results are compatible with the hypothesis that increases in the levels of adenosine in the basal forebrain, that occur during prolonged wakefulness, act through an A1 adenosine receptor and a second messenger system to increase the activity of the transcription factor NF-kappaB. We further hypothesize that some of the long duration effects of prolonged wakefulness/sleep deprivation on performance and physiology, often termed 'sleep debt', might be mediated through adenosine and its activation of NF-kappaB, which is known to alter the expression of several behavioral state regulatory factors.

Lighting conditions affect the levels of plasma gonadotropins differently in old and young castrated male rats.

It has been suggested that the decreased plasma levels of FSH and LH, often found in old male rats, are due to a diminished adenohypophyseal capacity to secrete the hormones and/or by changes in the hypothalamic regulatory system. We studied the effect of varying lighting conditions (12/12 h LD, continuous light and continuous darkness) on the plasma levels of the gonadotropins in castrated young adult and old male rats. We expected the sensitivity of the regulatory system to light to decrease or disappear with aging. The results for FSH supported this hypothesis: the plasma levels of FSH were more stable to changes of lighting conditions in the old rats. In disagreement with our hypothesis, the levels of LH were more sensitive to light changes in old than in young rats. It was concluded that the regulatory systems of the two hormones vary differently with age.

Orexin A and B levels in the hypothalamus of female rats: the effects of the estrous cycle and age.

OBJECTIVE: Orexins have been implicated in the regulation of several physiological functions including reproduction, energy balance and vigilance state. For successful reproduction, the precisely timed hormonal secretions of the estrous cycle must be combined with appropriate nutritional and vigilance states. The steroid- and nutritional state-dependent modulation of LH release by orexins, as well as an increase of vigilance, suggest that orexins may co-ordinate these functions in the course of the estrous cycle. DESIGN: We studied the brain tissue levels of orexins in the course of the estrous cycle in young and middle-aged rats. Young cycling rats (3 months old) and irregularly/non-cycling (7-9 months old) female rats were inspected for vaginal smears and serum hormone levels. METHODS: Tissue concentrations of orexin A and B were measured in the hypothalamus and lateral hypothalamus on different days of the estrous cycle. RESULTS: Orexin A concentration in the hypothalamus of young cycling rats was higher on the day of proestrus 5-6 h after the lights were switched on than on the other days of the estrous cycle at the same circadian time. Orexin B concentration was higher on both the day of proestrus and the day of estrus as compared with the days of diestrus. The hypothalamic concentrations of both orexin A and B in the non-cycling middle-aged rats were lower than those in cycling rats on the days of proestrus and estrus. CONCLUSIONS: We have concluded that the high hypothalamic concentration of orexins on the day of proestrus may contribute to the LH and prolactin surges. High orexin A levels may also contribute to the decreased amount of sleep on the day of proestrus.

Adenosine and behavioral state control: adenosine increases c-Fos protein and AP1 binding in basal forebrain of rats.

In several brain areas, extracellular adenosine (AD) levels are higher during waking than sleep and during prolonged wakefulness AD levels in the basal forebrain increase progressively. Similarly, c-Fos levels in several brain areas are higher during waking than sleep and remain elevated during prolonged wakefulness. In the present study, we investigated the effect of extracellular AD levels on c-Fos protein and activator protein-1 (AP1) binding in the basal forebrain of rats. Increased levels of extracellular AD were induced either by keeping the animals awake, or by local perfusion of AD into the basal forebrain. During prolonged wakefulness extracellular AD concentration was monitored using in vivo microdialysis. The effect of AD perfusion on the behavioral states was recorded using polysomnography. At the end of the perfusion period the basal forebrain tissue was analyzed for the levels of c-Fos protein and AP1 binding. In vivo microdialysis measurements showed an increase in AD levels with prolonged wakefulness. Unilateral perfusion of AD (300 microM) increased non-REM sleep and delta power (0.5 to 4 Hz) when compared to rats perfused with artificial CSF. The levels of c-Fos protein and the AP1 DNA binding were high in the basal forebrain of both sleep-deprived animals and in animals perfused with AD. The results suggest that AD might mediate, at least in part, the long term effects of sleep deprivation by inducing c-Fos protein and subsequent AP1 binding.

Neonatal administration of a GABA-T inhibitor alters central GABAA receptor mechanisms and alcohol drinking in adult rats.

Long-term effects of chronic treatment with a GABA-T (GABA-transaminase) inhibitor, ethanolamine O-sulphate (EOS) (200 mg/kg/day for the postnatal days 3-21) on the binding parameters of GABAA receptors, hypothalamic monoamines and subsequent behavior were studied in Wistar rats. At the age of 1 month, EOS-treated rats showed reduced activity in the open-field and, at the age of 4 months, their voluntary alcohol consumption was increased. No changes were seen in Porsolt's swim test or in the plus-maze test. Weight gain was significantly retarded in EOS-treated rats. Maximal stimulation of [3H] flunitrazepam binding by GABA was decreased in the cerebral cortex and the EC50-value for the GABA stimulation increased in the hippocampus in the EOS rats at the age of 4 months. EOS treatment did not alter the cerebellar diazepam sensitive and insensitive binding components of the imidazobenzodiazepine [3H]Ro 15-4513. No changes were observed in the hypothalamic monoamine concentrations. The results are in agreement with the idea that GABA-T inhibitor treatment permanently alters GABAA mechanisms. Moreover, altering the CNS GABA level during development increases adult alcohol intake in rat.

Sleep deprivation increases brain serotonin turnover in the rat.

IN order to study possible time-dependent changes in serotonin metabolism in rat brain, male Wistar rats were subjected to 3, 6 or 12 h total sleep deprivation (SD) by gentle handling. In addition two groups of rats subjected first to 6 h SD were allowed 2 or 4 h rebound sleep. Tissue concentrations of serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were measured from several brain areas using HPLC/ECD. SD significantly increased the 5-HIAA/5-HT ratio in frontal cortex, hippocampus, hypothalamus and brain stem, indicating increased 5-HT turnover in those areas. After 2 and 4 h rebound sleep, the 5-HIAA/5-HT ratio was similar to that in controls. We conclude that a short SD increases 5-HT turnover in the rat brain for the duration of SD only.