Repeated co-option of HMG-box genes for sex determination in brown algae and animals

In many eukaryotes, genetic sex determination is not governed by XX/XY or ZW/ZZ systems but by a specialized region on the poorly studied U (female) or V (male) sex chromosomes. Previous studies have hinted at the existence of a dominant male-sex factor on the V chromosome in brown algae, a group of multicellular eukaryotes distantly related to animals and plants. The nature of this factor has remained elusive. Here, we demonstrate that an HMG-box gene acts as the male-determining factor in brown algae, mirroring the role HMG-box genes play in sex determination in animals. Over a billion-year evolutionary timeline, these lineages have independently co-opted the HMG box for male determination, representing a paradigm for evolution's ability to recurrently use the same genetic "toolkit" to accomplish similar tasks.

Evolution of life cycles and reproductive traits: Insights from the brown algae

A vast diversity of types of life cycles exists in nature, and several theories have been advanced to explain how this diversity has evolved and how each type of life cycle is retained over evolutionary time. Here, we exploited the diversity of life cycles and reproductive traits of the brown algae (Phaeophyceae) to test several hypotheses on the evolution of life cycles. We investigated the evolutionary dynamics of four life-history traits: life cycle, sexual system, level of gamete dimorphism and gamete parthenogenetic capacity. We assigned states to up to 77 representative species of the taxonomic diversity of the brown algal group, in a multi-gene phylogeny. We used maximum likelihood and Bayesian analyses of correlated evolution, while taking the phylogeny into account, to test for correlations between traits and to investigate the chronological sequence of trait acquisition. Our analyses are consistent with the prediction that diploid growth evolves when sexual reproduction is preferred over asexual reproduction, possibly because it allows the complementation of deleterious mutations. We also found that haploid sex determination is ancestral in relation to diploid sex determination. However, our results could not address whether increased zygotic and diploid growth are associated with increased sexual dimorphism. Our analyses suggest that in the brown algae, isogamous species evolved from anisogamous ancestors, contrary to the commonly reported pattern where evolution proceeds from isogamy to anisogamy.

Evolution of life cycles and reproductive traits: Insights from the brown algae

A vast diversity of types of life cycles exists in nature, and several theories have been advanced to explain how this diversity has evolved and how each type of life cycle is retained over evolutionary time. Here, we exploited the diversity of life cycles and reproductive traits of the brown algae (Phaeophyceae) to test several hypotheses on the evolution of life cycles. We investigated the evolutionary dynamics of four life-history traits: life cycle, sexual system, level of gamete dimorphism and gamete parthenogenetic capacity. We assigned states to up to 77 representative species of the taxonomic diversity of the brown algal group, in a multi-gene phylogeny. We used maximum likelihood and Bayesian analyses of correlated evolution, while taking the phylogeny into account, to test for correlations between traits and to investigate the chronological sequence of trait acquisition. Our analyses are consistent with the prediction that diploid growth evolves when sexual reproduction is preferred over asexual reproduction, possibly because it allows the complementation of deleterious mutations. We also found that haploid sex determination is ancestral in relation to diploid sex determination. However, our results could not address whether increased zygotic and diploid growth are associated with increased sexual dimorphism. Our analyses suggest that in the brown algae, isogamous species evolved from anisogamous ancestors, contrary to the commonly reported pattern where evolution proceeds from isogamy to anisogamy.

Efficacy and safety of MIN-101: A new drug for the treatment of negative symptoms in schizophrenia a 12-week randomized, double blind, placebo-controlled trial

Objective

To compare the efficacy, safety, and tolerability of MIN-101, a compound with high affinities for sigma 2 and 5-HT 2A receptors, to placebo in treating negative symptoms, in stabilized patients with schizophrenia.

Methods

This multi-national phase 2b trial enrolled 244 patients with schizophrenia who were symptomatically stable for ≥ 3 months prior to entering the trial and had scores ≥ 20 negative subscale of the PANSS. Patients were randomized to monotherapy with MIN-101 32 mg/day, MIN-101 64 mg/day or placebo in a 1:1:1 ratio. The primary endpoint was the PANSS negative symptom score based on the five factors (pentagonal) model.

Results

Statistically significant reduction in the primary endpoint score was demonstrated for MIN-101 32 mg and 64 mg compared to placebo (P ≤ 0.022, ES 0.45 and ≤ 0.003, ES 0.58, respectively). This was supported by similar effects on most of the secondary measurements including: the PANSS three factors negative symptoms subscale, PANSS total score, CGI, BACS, CDSS, and PSP. There were no statistically significant differences in PANSS positive subscale scores between MIN-101 and placebo. No weight gain or clinically significant changes in vital sings, prolactin levels, routine laboratory values, metabolic indices and extrapyramidal symptom scores (EPS) were observed.

Conclusions

Since positive symptoms and EPS did not change, the improvement in negative symptoms was not secondary to improvement in positive symptoms or EPS, suggesting that MIN-101 might be the first specific treatment to have a direct effect on negative symptoms.

Disclosure of interest

I have received consultant fees from Minerva Neuroscience the sponsor of this trial and own stock of Minerva Neuroscience

The Pseudoautosomal Regions of the U/V Sex Chromosomes of the Brown Alga Ectocarpus Exhibit Unusual Features

The recombining regions of sex chromosomes (pseudoautosomal regions, PARs) are predicted to exhibit unusual features due to their being genetically linked to the nonrecombining, sex-determining region. This phenomenon is expected to occur in both diploid (XY, ZW) and haploid (UV) sexual systems, with slightly different consequences for UV sexual systems because of the absence of masking during the haploid phase (when sex is expressed) and because there is no homozygous sex in these systems. Despite a considerable amount of theoretical work on PAR genetics and evolution, these genomic regions have remained poorly characterized empirically. We show here that although the PARs of the U/V sex chromosomes of the brown alga Ectocarpus recombine at a similar rate to autosomal regions of the genome, they exhibit many genomic features typical of nonrecombining regions. The PARs were enriched in clusters of genes that are preferentially, and often exclusively, expressed during the sporophyte generation of the life cycle, and many of these genes appear to have evolved since the Ectocarpales diverged from other brown algal lineages. A modeling-based approach was used to investigate possible evolutionary mechanisms underlying this enrichment in sporophyte-biased genes. Our results are consistent with the evolution of the PAR in haploid systems being influenced by differential selection pressures in males and females acting on alleles that are advantageous during the sporophyte generation of the life cycle.

Sexual dimorphism and the evolution of sex-biased gene expression in the brown alga ectocarpus

Males and females often have marked phenotypic differences, and the expression of these dissimilarities invariably involves sex differences in gene expression. Sex-biased gene expression has been well characterized in animal species, where a high proportion of the genome may be differentially regulated in males and females during development. Male-biased genes tend to evolve more rapidly than female-biased genes, implying differences in the strength of the selective forces acting on the two sexes. Analyses of sex-biased gene expression have focused on organisms that exhibit separate sexes during the diploid phase of the life cycle (diploid sexual systems), but the genetic nature of the sexual system is expected to influence the evolutionary trajectories of sex-biased genes. We analyze here the patterns of sex-biased gene expression in Ectocarpus, a brown alga with haploid sex determination (dioicy) and a low level of phenotypic sexual dimorphism. In Ectocarpus, female-biased genes were found to be evolving as rapidly as male-biased genes. Moreover, genes expressed at fertility showed faster rates of evolution than genes expressed in immature gametophytes. Both male- and female-biased genes had a greater proportion of sites experiencing positive selection, suggesting that their accelerated evolution is at least partly driven by adaptive evolution. Gene duplication appears to have played a significant role in the generation of sex-biased genes in Ectocarpus, expanding previous models that propose this mechanism for the resolution of sexual antagonism in diploid systems. The patterns of sex-biased gene expression in Ectocarpus are consistent both with predicted characteristics of UV (haploid) sexual systems and with the distinctive aspects of this organism's reproductive biology.

Pharmacokinetic profile of SKP-1041, a modified release formulation of zaleplon

OBJECTIVES

Two investigations aimed to define the pharmacokinetic profile of a modified-release preparation of zaleplon (SKP-1041).

METHODS

Protocol SOM001 was a 5-way crossover, double-blind, randomized trial comparing three novel modified-release formulations of zaleplon 15 mg (SKP-1041A, SKP-1041B, SKP-1041C) to placebo and immediate-release zaleplon 10 mg. Protocol SOM002 was a randomized, crossover, open-label trial to compare the pharmacokinetics of SKP-1041B after day and night administration. In SOM001, study drug was administered at 9:00 a.m. (fasted); blood samples were obtained beginning 1 h predose through 12 h postdose. In study SOM002, study drug was administered at 9:00 a.m. or 10:30 p.m.; blood samples were obtained beginning 1 h predose through 12 h postdose. Subjects were 19 (SOM001) and 23 (SOM002) healthy adults between ages 20-46.

RESULTS

Dose-normalized total AUCs for modified-release preparations A, B, C and immediate-release zaleplon were not significantly different; peak plasma concentrations were similar for A and B, and both were significantly higher than C. Time to peak plasma concentration for A, B, and C were 4-5 h compared to 1.5 h for immediate-release zaleplon; mean terminal phase half-life was in the range 1-2 h for A, B and immediate-release zaleplon. No significant differences were noted between day and night administration in the SOM002 study.

CONCLUSIONS

Zaleplon, 15 mg, in a novel, modified-release formulation (SKP-1041) had a time to peak plasma concentrations at 4-5 h postdose compared to 1.5 h for immediate-release zaleplon, 10 mg. The pharmacokinetic profile suggests this formulation may be useful for treating middle-of-the-night awakening.

One milligram of lorazepam does not decrease anxiety induced by CCK-4 in healthy volunteers: investigation of neural correlates with BOLD MRI

Benzodiazepine effects on cholecystokinin tetrapeptide (CCK-4)-induced panic attack (PA) in humans are incompletely characterized, in particular on the neurofunctional level. This work explores the effects of lorazepam on brain activity and behavioral and physiological symptoms related to CCK-4-induced PA in healthy volunteers. Twenty-one male volunteers received 1 mg of lorazepam or placebo orally, 2 hours before an injection of 0.9% saline solution followed by 50 µg of CCK-4 during functional magnetic resonance imaging (fMRI) and heart rate recording. Panic attacks were defined using the panic symptom scale (PSS). In addition, the Y1-STAI (state anxiety) and the Bond & Lader Visual Analogue Scale (VAS) were used. Eleven subjects were classified as panickers. CCK-4 induced behavioral anxiety and cardiovascular effects along with cerebral activation in anxiety-related brain regions. Overall, lorazepam did not significantly modify the anxiogenic and cardiovascular effects of CCK-4. Regarding CCK-4-induced brain activation, lorazepam did not reduce activity in the insulae and cingulate gyrus of panickers. One milligram of lorazepam was not sufficient to reverse strong panicogenic effects, but decreased brain activity in the case of mild anxiety.

Effects of lorazepam on brain activity pattern during an anxiety symptom provocation challenge

Human models of anxiety are useful to develop new effective anxiolytics. The objective of this study was to use functional magnetic resonance imaging (fMRI) to test the hypothesis that a single dose of lorazepam modifies brain activation during an anxiety challenge. Eighteen healthy male subjects underwent fMRI associated with a challenge based on the anticipation of aversive electrical stimulations after pretreatment, either with placebo or with 1.0 mg of oral lorazepam. Anxiety was rated before fMRI and after, referring to the threat condition periods, using State Trait Anxiety Inventory (STAI) and Hamilton scales. The conditioning procedure induced anxiety, as indicated by clinical rating score changes. Lorazepam did not modify anxiety rating as compared to placebo. Lorazepam reduced cerebral activity in superior frontal gyrus, anterior insula/inferior frontal gyrus and cingulate gyrus. The current finding provides the first evidence of the modulatory effects of an established anxiolytic agent on brain activation related to anticipatory anxiety.

The effect of aging on the inhibitory function in middle-aged subjects: a functional MRI study coupled with a color-matched Stroop task

OBJECTIVE

The effects of aging on the inhibitory function are largely described in the neuroimaging literature but little data is available on the beginning of this age-related impairment.

METHODS

In this study, we described the cortical activation of middle-aged (mean age +/- standard error to the mean, 51.7 +/- 3.1) subjects compared to young (26.8 +/- 3.4) and elderly subjects (62.8 +/- 3) while they performed a color-matched Stroop task during functional magnetic resonance imaging. The task consisted in identifying the printing color of a word regardless of its meaning. Three conditions were defined depending on the meaning of this word; neutral (no meaning), congruent (color name matching the printing color), incongruent (color name mismatching the printing color), with interference effect in the latter.

RESULTS

Middle-aged subjects were as slow as elderly compared to young for all conditions and both were less accurate than young subjects during interference condition. Elderly showed an activity more bilateral and greater in the parietal lobule, the dorsolateral and ventrolateral prefrontal cortex (DLPFC, VLPFC) during both congruent and incongruent conditions compared to young. Middle-aged showed an intermediary level of activity between those of elderly and young subjects in the left DLPFC, VLPFC and parietal lobule only during incongruent condition.

CONCLUSION

These results suggested that the age-related impairment of the inhibitory process could already occur around the age of 50 years and consist in an increase of the activity in the left prefrontal and parietal cortex before increasing more and becoming bilateral around the age of 60 years.

Psychotropic profile of S 17092, a prolyl endopeptidase inhibitor, using quantitative EEG in young healthy volunteers

The central activity of S 17092, a prolyl endopeptidase (PEP) inhibitor, was investigated by quantitative electroencephalography (qEEG) in 48 young healthy men participating in a double-blind, randomized, placebo-controlled, cross-over study. S 17092 (100, 200, 400 or 600 mg) and placebo were administered once daily for 10 days in a rising multiple-dose scheme. EEG recordings were performed before and repeatedly from 0.5 to 24 h after dose on day 1 and day 10. PEP activity in plasma was also measured for the same periods. S 17092 appeared as a potent inhibitor of PEP activity at all doses, after both single and repeated administrations. EEG changes after acute doses were slight and of short duration, mainly characterized by increased relative alpha 1 power, suggesting a vigilance-promoting EEG profile. After repeated doses and more strikingly after a superimposed dose, increases in relative alpha 1 power were still present with additional increase in relative delta power and decreases in absolute fast alpha, fast beta, theta powers and total power at all doses. These EEG findings suggest that S 17092 might possess some mood-stabilizing potential in addition to its cognition-enhancing properties.

Ketamine effects on CNS responses assessed with MEG/EEG in a passive auditory sensory-gating paradigm: an attempt for modelling some symptoms of psychosis in man

Disturbances in integrative function have been consistentLy described in psychotic disorder; for instance, prepulse inhibition of the startle reflex (startle-PPI) which is a marker of sensory gating, is deficient in persons with schizophrenia. The N-methyl-D-aspartate antagonist ketamine produces in control subjects a spectrum of neurobehavioural symptoms like encountered in schizophrenia, and disrupts startle-PPI in animals. In the present study, we investigated in 12 healthy subjects whether ketamine would reduce sensory-gating in auditory responses at doses which produce psychotic symptoms. In a double-blind, crossover design loading doses of 0.024, 0.081 and 0.27 mg/kg or saline were employed, followed by maintenance infusion for 120 min. A passive paradigm has been developed which consisted in tone bursts, preceded or not by a (near-threshold) click at intervals of 100 ms or 500 ms. Brain electromagnetic activity imaging of the responses to sound stimuli has been carried out by way of a 148-channel magnetoencephalography-system. Actual evoked response amplitudes and underlying equivalent current dipole strengths have been compared to multi-electrode evoked potentials from the scalp. A click stimulus is capable to inhibit test responses under placebo at the 100 ms interval. During maintenance infusion of ketamine at steady-state (for >30 min) after 0.27 mg/kg, no such amplitude changes were observed anymore (p <0.05) and under these circumstances significant increases in Brief Psychiatric Rating scale and Scale for the Assessment of Negative Symptoms scores were evidenced (p < 0.001). Intermediate effects have been observed when the dose was lowered to 0.081 mg/kg. The present results have shown that ketamine may induce a psychotic-like clinical state associated with gating deficits in healthy subjects.

Effects of TC-1734 (AZD3480), a selective neuronal nicotinic receptor agonist, on cognitive performance and the EEG of young healthy male volunteers

OBJECTIVES

The aim of this study was to get insight into the central effects of TC-1734 (renamed AZD3480), a selective agonist at the neuronal nicotinic receptor of the alpha4beta2 subtype.

MATERIALS AND METHODS

Electroencephalography (EEG) techniques and computerized cognitive tests were performed in young, healthy male volunteers during two double-blind and placebo-controlled studies: a rising single dose crossover study (from 2 to 320 mg) and a rising repeated dose study with a parallel group design (50, 100, and 200 mg).

RESULTS

In contrast to acute administration, administration of AZD3480 over 10 days produced statistically significant enhancement of several cognitive measures (attention and episodic memory) compared to placebo. Regarding EEG data, AZD3480 showed acceleration of the alpha centroid and of the alpha peak in the single-dose study. This EEG profile of the acceleration type was confirmed in the repeated dose study on both day 1 and day 10, with the greatest effect observed with the highest dose. The EEG pattern shown for AZD3480 was consistent with that previously described with other drugs known to improve attention and vigilance (including nicotine). In addition, subjects dosed with AZD3480 showed a statistically significant increase in mismatch negativity (MMN) amplitude at 50 and 200 mg while reducing MMN latency (200 mg only), suggesting an improvement of pre-attentional mechanisms.

CONCLUSION

These early data in healthy subjects provide encouragement to consider development of AZD3480 as a novel agent for the treatment of cognitive decline in the elderly, including age-associated memory impairment and/or dementia of the Alzheimer's type.

Pharmacokinetics and safety profile of ispronicline (TC-1734), a new brain nicotinic receptor partial agonist, in young healthy male volunteers

Recent research suggests that drugs activating nicotine acetylcholine receptors might be promising therapy in cognitive decline seen in the elderly, including Alzheimer's disease. Ispronicline (TC-1734), a brain-selective alpha4beta2 nicotine acetylcholine receptor partial agonist, has shown memory-enhancing properties in rodents and a good tolerability profile. The safety and the full pharmacokinetic profile of TC-1734 and its N-desalkylated metabolite, TC-1784, were investigated in 2 phase I studies, and results are reported in this article. Study A used a double-blind, placebo-controlled, crossover design with a rising single-dose scheme (2-320 mg). Study B used a double-blind, placebo-controlled, parallel-group design with a rising multiple-dose scheme (doses: 50, 100, and 200 mg, once daily, x 10 days). Cmax of TC-1734 was reached around 1 to 2 hours postdose, and mean terminal half-life (t1/2) ranged from 3 to 5.3 hours (single doses) and from 2.7 to 8.8 hours (repeated doses). No accumulation of TC-1734 was observed after 10 days. Renal clearance appeared to be a minor method of elimination of TC-1734 and TC-1784. A high interindividual variability was noted for all parameters. Across the dose ranges explored, TC-1734 was safe and well tolerated. No changes of clinical significance were seen on laboratory and cardiovascular parameters. Adverse events were generally of mild to moderate intensity, with dizziness and headache being reported most frequently.

Effects of acamprosate on sleep during alcohol withdrawal: A double-blind placebo-controlled polysomnographic study in alcohol-dependent subjects

BACKGROUND

Sleep disturbances are frequently encountered in alcohol-dependent patients. Drugs improving sleep during abstinence from alcohol may play an important role in the recovery process.

METHODS

In the present study, the effects of acamprosate, a drug successfully used in maintaining abstinence following alcohol withdrawal, were assessed by polysomnographic recordings. A parallel double-blind placebo-controlled study was conducted in 24 male DSM-IV alcohol-dependent subjects aged 35.9+/-1.2 years. Treatments (2 tablets of 333 mg acamprosate vs placebo t.i.d.) were initiated 8 days before alcohol withdrawal and continued during the 15 days following alcohol withdrawal. Polysomnographic assessments were recorded during acute withdrawal (the first 2 nights following withdrawal) and during postwithdrawal abstinence (the last 2 nights of the trial).

RESULTS

Results show that, compared with placebo, acamprosate decreased wake time after sleep onset and increased stage 3 and REM sleep latency (all treatment effects with a p < 0.05 significance). Withdrawal effects themselves were also demonstrated as sleep efficiency (p < 0.01) and total sleep time (p < 0.05) were lower in abstinence nights versus withdrawal nights, whereas no significant treatment x withdrawal effect could be evidenced. Acamprosate was well tolerated during the entire course of the study.

CONCLUSIONS

The present study shows that acamprosate ameliorates both sleep continuity and sleep architecture parameters classically described as disturbed in alcohol-dependent patients. From a clinical perspective, it suggests that an 8-day acamprosate prewithdrawal treatment is well tolerated and can attenuate the sleep disturbances engendered by alcohol withdrawal in alcohol-dependent subjects.

Comparison of the effects of a 24-hour nicotine patch and a 16-hour nicotine patch on smoking urges and sleep

This randomized, open-label, crossover study was conducted to compare the effects of a 24-hr nicotine patch and a 16-hr nicotine patch on morning smoking urges and sleep quality of dependent smokers during a short period of cigarette abstinence. A total of 20 smokers (9 women and 11 men) smoking at least 20 cigarettes/day completed the two smoke-free study periods. For each period, cigarette abstinence started on the first evening and a nicotine patch was applied the next morning (for 16 or 24 hr), after baseline measures; a second patch was applied the next morning, 1 hr before the end of the experimental period. Smoking urges, mood and behavior self-reports, psychomotor performance, and polysomnographic recordings were compared between the two types of nicotine patch according to changes from baseline. Both patches decreased morning smoking urges, although results were significantly superior for the 24-hr patch. Furthermore, the 24-hr patch was more effective than the 16-hr patch in reducing the positive reinforcing dimension of smoking urges. Regarding polysomnographic recordings, the proportion of slow wave sleep was significantly increased from baseline with the 24-hr patch compared with the 16-hr patch. As for psychomotor performance measured through the critical flicker fusion test, significant improvement in morning alertness was observed in the 24-hr patch group. In conclusion, the 24-hr nicotine patch formulation is more effective than the 16-hr formulation in alleviating morning smoking urges and more specifically the positive reinforcing factor. The present findings do not support the idea that nicotine delivery during bedtime might disturb sleep, but rather it improves restorative sleep and postwaking arousal.

Functional magnetic resonance imaging characterization of CCK-4-induced panic attack and subsequent anticipatory anxiety

The main objective of this work was to study the functional markers of the clinical response to cholecystokinin tetrapeptide (CCK-4). Twelve healthy male subjects were challenged with CCK-4 and simultaneously underwent functional magnetic resonance imaging (fMRI) recording. Since anticipatory anxiety (AA) is an intrinsic part of panic disorder, a behavioral paradigm, using the threat of being administered a second injection of CCK-4, has been developed to investigate induced AA. The study was composed of three fMRI scans according to an open design. During first and second scan, subjects were injected with placebo and CCK-4, respectively. The third scan was the AA challenge. CCK-4 administration induced physiological and psychological symptoms of anxiety that met the criteria for a panic attack in 8 subjects, as well as cerebral activation in anxiety-related brain regions. Clinical and physiological response intensity was consistent with cerebral activity extent and robustness. fMRI proved more sensitive than clinical assessment in evidencing the effects of the AA challenge. The latter induced brain activation, different from that obtained on CCK-4 and during placebo injection, that was likely related to anxiety. The method applied in this study is suitable for the study of anxiety using fMRI.

Sleep effects of a 24-h versus a 16-h nicotine patch: A polysomnographic study during smoking cessation

BACKGROUND AND PURPOSE

Sleep disturbance is a common symptom of tobacco withdrawal and might contribute to early relapse vulnerability in abstinent smokers. This study was designed to compare the effects on sleep of nicotine patches applied either for 24 h (Nicopatch) or 16 h (Nicorette).

PATIENTS AND METHODS

During a short smoking cessation period (48 h), this open-label, randomised, two-period crossover study compared the effects on sleep of the two nicotine patches in 20 heavy smokers (9 women, 11 men). During each period, polysomnographic recordings were performed from 12 pm to 7 am for two consecutive nights (baseline and treatment nights). Smoking cessation started from 8 pm the day of the baseline sleep recordings, and treatments were applied around 8 am the following morning.

RESULTS

Compared to the 16-h nicotine patch, smokers who received the 24-h nicotine patch experienced significantly less microarousals, a greater proportion of slow wave sleep, a higher REM density and higher rapid eye movement (REM) beta activities.

CONCLUSIONS

The results of this study suggest that a 24-h nicotine patch is more efficient than a 16-h nicotine patch to alleviate tobacco withdrawal-induced sleep disturbances.

Ability of a new oral nicotine substitute to reduce smoking urge in moderate smokers

The aim of this study was to assess the effectiveness of a new nicotine lozenge ( Nicopass 1.5 mg) in reducing smoking urge after an overnight abstinence. Twenty-four moderate smokers participated in a randomized, double-blind, placebo-controlled, 2-period crossover trial. The results showed that 1.5 mg-nicotine lozenge is superior to placebo in reducing smoking urge (p = 0.0001). In addition, nicotine lozenge, but not placebo, significantly improved vigilance and psychomotor performances (p < 0.05) and displayed a cardiac chronotropic effect. Thus, the 1.5-mg nicotine lozenge appears as an effective aid to alleviate acute tobacco withdrawal symptoms in moderate smokers.

Next-day residual effects of hypnotics in DSM-IV primary insomnia: a driving simulator study with simultaneous electroencephalogram monitoring

RATIONALE

Most studies that investigated the next-day residual effects of hypnotic drugs on daytime driving performances were performed on healthy subjects and after a single drug administration.

OBJECTIVES

In the present study, we further examine whether the results of these studies could be generalised to insomniac patients and after repeated drug administration.

METHOD

Single and repeated (7 day) doses of zolpidem (10 mg), zopiclone (7.5 mg), lormetazepam (1 mg) or placebo were administered at bedtime in a crossover design to 23 patients (9 men and 14 women aged 38.8+/-2.0 years) with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) primary insomnia. Driving tests were performed 9-11 h post-dose.

RESULTS

Results showed that treatment effects were evidenced for subjective sleep, for driving abilities, and for electroencephalogram (EEG) recorded before (resting EEG) and during the driving simulation test (driving EEG). Compared to placebo, zopiclone increased the number of collisions and lormetazepam increased deviation from speed limit and deviation from absolute speed, whereas zolpidem did not differentiate from placebo on these analyses. EEG recordings showed that in contrast to zolpidem, lormetazepam and zopiclone induced typical benzodiazepine-like alterations, suggesting that next-day poor driving performance could relate to a prolonged central nervous system effect of these two hypnotics.

CONCLUSION

The present results corroborate studies on healthy volunteers showing that residual effects of hypnotics increase with their half-lives. The results further suggest that drugs preserving physiological EEG rhythms before and during the driving simulation test 9-11 h post-dose, such as zolpidem, do not influence next-day driving abilities.

Pharmacodynamic effects of acamprosate on markers of cerebral function in alcohol-dependent subjects administered as pretreatment and during alcohol abstinence

Animal studies suggested that acamprosate modulates neuronal hyperexcitability of acute alcohol withdrawal, acting through the glutamatergic neurotransmission. In the present study, we further investigated whether treatment with acamprosate could attenuate the post-alcohol withdrawal hyperexcitability or hyperarousal in humans using brain magnetoencephalography mapping of spontaneous fields. A double-blind, randomised, placebo-controlled study with a parallel group design comparing 2,000 mg/day of acamprosate versus placebo was conducted in alcohol-dependent subjects meeting DSM-IV criteria for alcohol dependence. Treatments were initiated 8 days before alcohol withdrawal and prolonged during the 15 following (abstinence) days. The study demonstrated that during alcohol withdrawal, acamprosate decreased the arousal level as reflected by alpha slow-wave index (ASI) measurement. This effect was mostly evidenced in left parietotemporal regions and, to a lesser extent, in the contiguous anterior, posterior and right-sided regions. In the placebo group, on the contrary, ASI measures increased between day 2 (acute withdrawal) and day 14 (prolonged withdrawal). The present results suggest a sustained effect of acamprosate on the hyperexcitability state due to alcohol withdrawal in alcohol-dependent patients and that acamprosate may have a protective effect when administered 8 days before alcohol withdrawal.

Sleep microstructure around sleep onset differentiates major depressive insomnia from primary insomnia

In the present study we investigate whether alterations of sleep propensity or of wake propensity are implicated in sleep initiation disturbances encountered in major depressive insomnia and in primary insomnia. For this purpose, the time course of electroencephalogram (EEG) power density during the period preceding sleep onset and during the first non-rapid eye movement (REM) period was examined in three age and gender matched groups of 10 women and 11 men (healthy controls, primary insomniacs and depressive insomniacs). In contrast to healthy controls and depressive insomniacs, patients with primary insomnia did not experience a gradual decrease of their alpha and beta1 power during the sleep onset period and had a lower delta activity in the 5 min preceding sleep onset. Compared with the two other groups, depressive patients exhibit less dynamic changes in slow wave activity during the first non-REM period. The present results suggest that hyperarousal (high 'Process W') may mainly be implicated in the sleep initiation difficulties of primary insomniacs whereas the homeostatic sleep regulation process seems to be partially maintained. In our major depressed patients, the sleep initiation disturbances appeared to relate to a lower sleep pressure (low 'Process S') rather than to hyperarousal. This study supports the idea that different mechanisms are implicated in sleep disturbances experienced by primary insomniacs and major depressive insomniacs.

Characterization of the CNS effects of naftidrofuryl (Praxilène) by quantitative EEG and functional MRI: a study in healthy elderly subjects

In the present study, we investigated the effects of a single and a repeated (5 days) administration of naftidrofuryl, a serotonin 5-HT2 receptor inhibitor having neuroprotective properties, on functional brain physiology in male healthy elderly subjects, using quantitative electroencephalography (EEG) and functional magnetic resonance imaging (fMRI). Twelve subjects aged 60 +/- 3.8 years completed the quantitative EEG study, where the effects of 400 and 600 mg were assessed, and 12 other subjects (aged 56 +/- 4.7 years) completed the fMRI study, where the effect of 400 mg was assessed on the brain activation induced by the continuous performance test (CPT). Naftidrofuryl induced a transient reduction in alpha activity followed by a specific synchronisation of the 9.5- to 11-Hz EEG activity most pronounced after repeated administration. Such regimen also increased the CPT-induced brain activation visualized by way of fMRI. The results of the present study can be interpreted at the functional level that naftidrofuryl induced an improved level of vigilance or an increased capacity of alertness in healthy elderly subjects.

[Development of compounds active in insomnia: recent developments and methodological aspects]

Most pharmacotherapeutic treatments designed to treat insomnia target GABAergic activity globally in the brain. Development of new molecules having a more specific activity pathway should improve treatment efficacy and acceptance. Both subjective and objective criteria are needed to study drug efficacy. Data regarding drug effects on polysomnographic recordings are mandatory for the development of hypnotics. Whether the drug-induced sleep is comparable to normal sleep is tackled with the spectral analysis of the sleep EEG. Residual drug effects are assessed with a package of psychomotor and neurocognitive tests, and with the driving simulator test Clinical studies investigating drug efficacy and tolerability have to be conducted on large groups of patients carefully selected using polysomnographic recordings. Our knowledge about sleep will undoubtedly soon become available for treatment of insomnia.

Acute low single dose of apomorphine reduces periodic limb movements but has no significant effect on sleep arousals: a preliminary report

STUDY OBJECTIVES

To investigate the effects of apomorphine on the frequency of periodic limb movements during sleep (PLMS) and on sleep architecture.

DESIGN

Nine patients presenting PLMS (including eight patients with restless legs syndrome) underwent three consecutive night sleep recordings. They received a single dose of 0.5 mg subcutaneous apomorphine at bedtime the third night.

RESULTS

When computing PLMS during four 2-h periods of sleep, a significant period by apomorphine-effect was demonstrated, with a marked reduction of PLMS during the first 4 h post-injection (P < 0.01). No significant differences were found in sleep macroarchitecture between the three recorded nights, excepted a slight reduction in sleep latency during the third night (P < 0.05). Despite the decreased number of PLMS after apomorphine injection, there were significant changes neither in the total number of arousals nor in the index of arousals per hour of sleep.

CONCLUSION

Our results add further support to the dopaminergic hypothesis in the generation of PLMS. The persistence of arousals suggests that they are not simply the consequence of PLMS but a primary phenomenon, not related with the dopaminergic system.

Planning of pharmacodynamic trials: I. Specificity and possible solutions. II. Stability considerations under placebo and interpretation of drug effects on EEG

This workshop deals with the concept of quantitative electroencephalography (QEEG) to characterize the central effects of drugs. For proper interpretation, the circumstances under which data are obtained play an important role. To infer the size of variability in standard practice, we elaborated some computations for "placebo-treatment" in healthy volunteers, which helps to determine the threshold of drug effect detection. Simple rules for interpretation of multiple statistical comparisons were proposed and validation of dose effects were carried out with accepted reference compounds. Furthermore, psychotropic agents with comparable therapeutic indications often present similar modifications in EEG spectral composition (pharmaco-EEG profile). To extrapolate this concept, quantified wake-EEG is a rapid, validated technique for early psychopharmacological investigation of new psychotropic compounds (Phase I, healthy volunteers). Classification of drug-induced changes in cerebral activity at this stage forms a useful decision instrument in planning the long-term clinical scenario of drug development (Phases II and higher).

Effects of the selective activation of 5-HT3 receptors on sleep: a polysomnographic study in healthy volunteers

The respective role of various classes of central serotonin (5-HT) receptors in the regulation of sleep-wakefulness cycles has been the subject of many studies. Notably, it has been reported that 5-HT1A/B receptors are involved in the regulation of rapid eye movement sleep (REMS) and that 5-HT2A/C receptors participate in the control of slow wave sleep (SWS), but the role of 5-HT3 receptors is less well characterised. In this study we investigated the effects of SR 57227A, a potent and selective 5-HT3 agonist, on the sleep EEG of normal young male volunteers. SR 57227A (2.5, 5, 10, 20, 40 mg o.d. and 20 mg b.i.d.) or placebo were administered during 7 consecutive days in seven groups of ten subjects using a parallel group design. Sleep EEG recordings were performed on days 6 and 7 after an habituation session. SR 57227A produced a dose-dependent shift of REMS toward the end of the night without changing REMS and SWS duration nor altering sleep continuity. It suggests a role for the 5-HT3 receptor in the human sleep-wakefulness cycle and particularly in REMS regulation.

Morning and evening TSH response to TRH and sleep EEG disturbances in major depressive disorder

1. The aim of this study was to investigate hypothalamo-pituitary-thyroid axis (HPTA) functioning and sleep EEG disturbances in major depressive disorder. 2. Thyroid function was evaluated by determination of TSH levels before and after 8 AM and 11 PM TRH administration on the same day in a sample of 113 consecutively-admitted DSM-IV major depressed inpatients (72 females aged 44.3 +/- 13.0 and 41 males aged 45.7 +/- 10.7) that underwent sleep EEG recordings. 3. A blunted TSH response occurred in 15.9% for 8 AM deltaTSH (maximum increment above baseline at the 8 AM TRH challenge), in 39.8% for 11 PM deltaTSH and in 77% for deltadeltaTSH (difference between 11 PM deltaTSH and 8 AM deltaTSH). A negative correlation between deltadeltaTSH and duration of awakenings after sleep onset, and a shorter sleep onset latency in patients with a blunted 11 PM deltaTSH were found, but these two significant relationships disappeared after controlling for the effects of gender and age. 4. The present findings do not support the hypothesis that, in major depression, HPTA dysfunctioning, as reflected in TSH response to TRH, may be related to sleep EEG disturbances.

Electroencephalographic characterization of brain dopaminergic stimulation by apomorphine in healthy volunteers

Apomorphine, a dopamine receptor agonist (given in a dose of 0.75 mg s.c.), was administered to 8 healthy volunteers; electroencephalograph (EEG) and event-related potential (ERP) mapping were performed before dosing and 0.5, 1.5 and 2.5 h after dosing. Apomorphine caused an overall increase in beta activity at time 0.5 h in both absolute and relative energy; P300 and CNV ERPs were not significantly altered, although a tendency towards increased P300 latency was seen. The results confirm that the EEG mapping technique is sufficiently sensitive to monitor dopaminergic neurochemical stimulation by means of apomorphine. This could lead to a new, non-invasive and repeatable method for monitoring central neuronal systems which is more convenient to apply repeatedly than for example positron emission tomography techniques. Furthermore, electrophysiological techniques undoubtedly constitute an alternative to classical neuroendocrinological methods, allowing a more direct assessment of central nervous system neurotransmission. Finally, these EEG approaches could lead to better characterization of drugs acting on dopaminergic pathways, such as antipsychotics.

Alpha activity and cardiac correlates: three types of relationships during nocturnal sleep

OBJECTIVE

We examined simultaneously alpha activity and cardiac changes during nocturnal sleep, in order to differentiate non-rapid eye movement (NREM) sleep, REM sleep, and intra-sleep awakening.

METHODS

Ten male subjects displaying occasionally spontaneous intra-sleep awakenings underwent EEG and cardiac recordings during one experimental night. The heart rate and heart rate variability were calculated over 5 min periods. Heart rate variability was estimated: (1) by the ratio of low frequency (LF) to high frequency (HF) power calculated from spectral analysis of R-R intervals; and (2) by the interbeat autocorrelation coefficient of R-R intervals (rRR). EEG spectral analysis was performed using a fast Fourier transform algorithm.

RESULTS

Three types of relationships between alpha waves (8-13 Hz) and cardiac correlates could be distinguished. During NREM sleep, alpha activity and cardiac correlates showed opposite variations, with high levels of alpha power associated with decreased heart rate, rRR and LF/HF ratio, indicating low sympathetic activity. Conversely, during REM sleep, alpha activity was low whereas heart rate, rRR, and the LF/HF ratio peaked, indicating high sympathetic activity. During intra-sleep awakenings, alpha activity and cardiac correlates both increased. No difference in time-course between alpha 1 (8-10 Hz) and alpha 2 (10-13 Hz) activity could be shown. Alpha waves occurred in fronto-central areas during slow wave sleep (SWS), migrated to posterior areas during REM sleep, and were localized in occipital areas during intra-sleep awakenings.

CONCLUSIONS

These results suggest that alpha waves are not simply a sign of arousal, as is commonly thought. Fronto-central alpha waves, associated with decreased heart rate, possibly reflect sleep-maintaining processes.

Changes in EEG power density during sleep laboratory adaptation in depressed inpatients

BACKGROUND

The aim of the present study was to evaluate the first-night effect in depressed inpatients, using standard sleep measures as well as all-night spectral analysis of the sleep electroencephalogram (EEG).

METHODS

Eighteen drug-free, depressed inpatients were studied for 3 consecutive nights in the hospital sleep laboratory.

RESULTS

Visual sleep scoring results showed a slight but measurable first-night effect, characterized by a reduction of rapid eye movement (REM) sleep amount and increased wakefulness. Sleep EEG spectral analysis showed significantly reduced delta (p <.01) and theta (p <.05) power density in non-REM (NREM) sleep of the first night compared with that of the second and third nights. These differences were limited to the early part of the sleep period, a time during the night that is particularly vulnerable to the effects of depressive disorder. In contrast to the NREM sleep findings, spectral REM variables studied did not significantly vary across the three nights.

CONCLUSIONS

The results obtained suggest that first-night data should not be simply discarded but could be used in subsequent analyses and could be considered useful in the evaluation of the sleep of depressed patients.

Effects of serotonin-selective and classical antidepressants on the auditory P300 cognitive potential

The cognitive potential, P300, is a phenomenon frequently studied in relation to template matching of the brain. To understand the neurochemical mechanisms of its generation, we compared the effects of three antidepressants, fluoxetine, tianeptine and clomipramine after single and repeated application as well as after 1 week of withdrawal on the P300 and N200 waves in an auditory 'odd-ball' paradigm in three parallel groups of 10 healthy volunteers. Following single administration, both fluoxetine and clomipramine reduced (-39 +/- 14%, p < 0.01) the peak amplitude of P300 at the Pz electrode. For fluoxetine and tianeptine, reduced amplitudes of 19 +/- 7% and 24 +/- 11%, respectively, were found following 8 days of treatment, 2 h after administration. However, for clomipramine no additional diminution was found on day 8 with respect to day 1. Topographic distributions tended to be significantly modified at the frontal scalp area 1 h after the tianeptine administration on day 8, whereas the postdosing changes induced by fluoxetine were localised in the midline and right centrotemporal scalp regions. Only minor reductions in peak latencies have been observed. It can be concluded that serotonin selective drugs have a slower onset of P300 amplitude decrease than clomipramine, which has additional effects on monoaminergic and on cholinergic systems. These results suggest that serotonin has a regulatory function in the neurotransmission of cerebral structures which are involved in the evaluation of stimulus relevance.

Changes in EEG power density during sleep laboratory adaptation

First- and second-night effects on the electroencephalogram (EEG) were investigated by means of polygraphic sleep recordings and all-night spectral analysis. Eighteen normal subjects were studied for three consecutive nights in a hospital sleep laboratory. Visual sleep scoring showed that there was a first-night effect in normal subjects similar to that reported previously [increased wakefulness; decreased total sleep time, sleep efficiency, and rapid eye movement (REM) sleep]. Spectral analysis of the sleep EEG revealed important changes, most of which occurred in REM sleep. Increased delta, theta, and beta1 power densities accompanied by decreased mean frequency were seen in REM sleep in the second night. On the basis of REM sleep deprivation results previously published, our data suggest that the second night could be affected by partial REM sleep deprivation that occurred in the first night. Delta and theta power density values decreased in the first non-rapid eye movement episode of nights 1 and 2; this could result from increased REM sleep pressure. The overall consistency of spectral data in the first and second night with REM sleep findings derived from visual scoring in the first night lends further support to this hypothesis. The sleep disturbance experienced during the first night in a sleep laboratory may be a useful and valid model of transient insomnia. Therefore, we conclude that data from all nights recorded should be included in assessing a subject's sleep.

Temporal relationships between pulsatile cortisol secretion and electroencephalographic activity during sleep in man

A temporal link between slow wave sleep and low or decreasing cortisol release has been previously demonstrated. This relationship was re-evaluated in 15 healthy male subjects using spectral analysis of their sleep electroencephalogram (EEG). EEG activity in the delta, theta, alpha and beta bands was cross-correlated with cortisol secretory rates at 10-min intervals. For the period of pulsatile cortisol secretion, an inverse relationship was found with the delta band with an average cross-correlation coefficient of -0.505 (P < 0.0001). Variations in cortisol secretory rates coincided with or anticipated opposite variations in delta wave activity by 10 or 20 min. A significant positive correlation was found with theta activity, but alpha and beta bands did not elicit any systematic association with cortisol profiles. These results demonstrate a temporal association between cortisol secretory pulses and delta wave activity in man, suggesting the existence of a central control common to both variables.

A quantitative evaluation of the relationships between growth hormone secretion and delta wave electroencephalographic activity during normal sleep and after enrichment in delta waves

The existence of a relationship between growth hormone (GH) release and slow-wave sleep (SWS), often studied in the past using conventional scoring of sleep stages, remains controversial. In the present study, this relationship was reevaluated by spectral analysis of the sleep electroencephalogram (EEG) and deconvolution analysis of the plasma GH concentrations during normal nocturnal sleep and after enrichment in SWS by means of ritanserin, a selective 5-HT2 receptor antagonist. Eight healthy male subjects each participated in two randomized night studies after having received either a placebo or a 5-mg dose of ritanserin. They were subjected to 8 hours of polysomnography, including spectral analysis of the sleep EEG. Plasma GH levels were measured at 10-minute intervals. The mean delta absolute power and the mean GH secretory rates were significantly higher under ritanserin than under placebo for the first 3 hours after sleep onset (+24% and +29%, respectively). Their nocturnal profiles were significantly and positively correlated in all subjects (average r = 0.710 under placebo, 0.567 under ritanserin; p < 0.0001 in both cases). GH secretory pulses were found to be coincident with delta activity peaks in both directions. The amount of GH secreted during significant GH pulses was correlated with the amount of concomitant delta wave activity (r = 0.803 under placebo, r = 0.764 under ritanserin, p < 0.0001). Similarly, the amount of delta wave activity found during delta wave peaks was correlated with the amount of GH secreted concomitantly (r = 0.715 under placebo, r = 0.723 under ritanserin: p < 0.0001). These results demonstrate a close temporal and quantitative relationship between GH secretion and delta wave activity, which may be evidence of common stimulatory mechanisms.

Relationships between intact parathyroid hormone 24-hour profiles, sleep-wake cycle, and sleep electroencephalographic activity in man

To determine whether the 24-h intact PTH (iPTH) profile is influenced by the sleep-wake cycle, and whether iPTH pulses show a temporal relationship with internal sleep structure, eight normal young men were studied during 24 h under basal conditions, once with normal nighttime sleep from 2300-0700 h and once after a night of sleep deprivation followed by an 8-h period of daytime sleep from 0700-1500 h. During the 8-h nighttime sleep period, mean iPTH levels were significantly increased by +13% and mean iPTH pulse amplitudes by +31% as compared with the 8-h subsequent waking periods. During the 8 h of total sleep deprivation, mean iPTH levels were not significantly different from the corresponding period in nighttime sleep condition, but mean iPTH pulse amplitudes were significantly lower (P < 0.01). The 8-h daytime sleep period was associated with increased mean iPTH levels and mean iPTH pulse amplitudes (+15% and +57%, respectively, as compared with the corresponding period in nighttime sleep condition). The number of pulses was similar in both experimental series and was not influenced by sleep or by time of day. Analysis of coincidence between iPTH pulses, plasma ionized calcium and plasma phosphate pulses, and slow wave sleep, as well as with rapid eye movement sleep episodes, did not reveal any significant association. Cross-correlation analysis between iPTH, plasma ionized calcium, and plasma phosphate fluctuations during sleep also showed no systematic association. Seven other subjects were studied during a nighttime sleep period in which temporal relationships between iPTH and internal sleep structure were reevaluated using spectral analysis of the sleep electroencephalogram. Cross-correlation analysis between iPTH levels and delta-relative power fluctuations showed nonsignificant results, which confirms the lack of relationship with slow wave sleep. This study demonstrates that the iPTH 24-h profile is influenced by sleep processes with a weak circadian component. However, iPTH pulses are not temporally linked with sleep electroencephalographic activity nor with calcemia and phosphatemia fluctuations. This evidence raises questions about the origin of iPTH pulses.

5-HT2 receptors are partially involved in the relationship between renin release and delta relative power

A strong relationship was previously described between the nocturnal oscillations of plasma renin activity (PRA) and the sleep cycles, with levels of PRA that increase during non rapid eye movement sleep and decrease during rapid eye movement sleep. This study was designed to determine whether ritanserin, a 5-hydroxytryptamine-2 (5-HT2) receptor antagonist known to increase slow wave sleep both in human and in animals and to decrease plasma renin activity response to serotonergic stimulation in the rat, would uncouple this relationship. Eight subjects underwent two randomized night studies after having received either placebo or 5 mg ritanserin administered in the morning. They were subjected to 8 hour polysomnography, including spectral analysis of the electroencephalogram and to continuous blood sampling. Blood was sampled from 2300 to 700h every 10 min and plasma renin activity (PRA) was measured by radioimmunoassay of angiotensin 1. The nocturnal profiles were analysed using the pulse detection program ULTRA. Ritanserin produced the expected increase in slow wave sleep (SWS) duration (132 +/- 10 min under ritanserin vs 72 +/- 9 min under placebo; p < 0.001) and a significant increase in delta relative power (69 +/- 2% under ritanserin vs 60 +/- 2% under placebo; p < 0.01). The mean overnight PRA levels had a tendency to decrease under ritanserin (1.66 +/- 0.34 ngAngl/ml per h under ritanserin vs 1.48 +/- 0.31 ngAngl/ml per h under placebo; p = 0.08). Individual PRA oscillations were preserved and remained strongly associated with delta power oscillations. PRA peak levels were similar in both experimental conditions, but the absolute amplitude of the oscillations was decreased under ritanserin (1.50 +/- 0.36 ngAngl/ml per h vs 1.04 +/- 0.14 ngAngl/ml per h; p < 0.05). These results demonstrate that ritanserin, at a dose that augments delta power, only weakly affects renin release, which suggests that 5-HT2 receptors are only partially involved in the processes coupling renin release and SWS and that other mechanisms probably control the sleep-associated variations in PRA.

Low-dimensional dynamic self-organization in delta-sleep: effect of partial sleep deprivation

Studies on extended data including 37 electroencephalographic (EEC) records of delta-sleep, each 10(3) s long (six subjects: up to seven nights per subject, comprising normal sleep, partial deprivation and recovery), confirmed earlier conclusions that rare episodes of low-dimensional dynamic self-organization, with life-times between 10 and 20 s, are present in stage 4 sleep. Particular care was taken of the Theiler correction which, in some delta-sleep signals, required the deletion of trajectory points covering nearly one pseudo-period. The percentage of segments showing an episode, i.e. the attractor probability, decreased with a change in sleep conditions either deprivation or recovery prior to the next deprivation. Repetition of deprivation over three nights resulted in an adaptation process, manifested by an increase in attractor probability. After the sharp decrease in probability observed when recovery was established prior to the next deprivation, and on return to normal conditions of sleep at 2200 hours, the probability was immediately close to that observed in normal baseline sleep conditions free of any interference. The observation of a definite effect of sleep deprivation and recovery upon the number of stage 4 attractors observed provides a line of approach to the physiological significance of the probability of such attractors.

Pharmacoelectroencephalographic profile of befloxatone, a new reversible MAO-A inhibitor, in healthy subjects

The pharmaco-EEG profile and the effects on P300 and CNV of befloxatone, a new selective and reversible MAO-A inhibitor, were assessed in a randomized, double-blind, placebo-controlled, 4-way crossover study. Twelve healthy young male volunteers were administered single doses of 2.5, 10 and 20 mg befloxatone and placebo separated by a 1-week washout. The EEG data were recorded before and at least 6 h after drug administration, by means of 28 leads allowing topographical analysis of the results. MAO inhibition, subjective effects and safety variables were also investigated. Statistical analysis was performed by means of the SDT method. Befloxatone induced dose-related EEG changes which occurred rapidly, peaked between 0.5 and 2 h and lasted at least until 6 h after drug administration. The EEG changes were characterized by an increase in absolute and/or relative alpha power, mainly alpha 1, after the 3 doses and a theta power increase after 10 and 20 mg only. These changes occurred mainly over the centroparietotemporal areas. Concerning the event-related potential, P300 latency of the auditory evoked potentials did not change. The P300 and CNV mean topographic amplitudes were decreased, between 0.5 and 2 h, after the two lowest doses for the P300 and the 3 doses for the CNV. After administration of 2.5, 10 and 20 mg, MAO inhibitions was shown by respectively 38, 76 and 81% reduction in plasma free 3, 4-dihydroxyphenylglycol reached after 2-4 h. Such a pharmaco-EEG profile, occurring at doses inducing MAO-A inhibition, is similar to those already described with nonsedative antidepressants.

Sleep stage scoring using the neural network model: comparison between visual and automatic analysis in normal subjects and patients

In this paper, we compare and analyze the results from automatic analysis and visual scoring of nocturnal sleep recordings. The validation is based on a sleep recording set of 60 subjects (33 males and 27 females), consisting of three groups: 20 normal controls subjects, 20 depressed patients and 20 insomniac patients treated with a benzodiazepine. The inter-expert variability estimated from these 60 recordings (61,949 epochs) indicated an average agreement rate of 87.5% between two experts on the basis of 30-second epochs. The automatic scoring system, compared in the same way with one expert, achieved an average agreement rate of 82.3%, without expert supervision. By adding expert supervision for ambiguous and unknown epochs, detected by computation of an uncertainty index and unknown rejection, the automatic/expert agreement grew from 82.3% to 90%, with supervision over only 20% of the night. Bearing in mind the composition and the size of the test sample, the automated sleep staging system achieved a satisfactory performance level and may be considered a useful alternative to visual sleep stage scoring for large-scale investigations of human sleep.

Temporal link between plasma thyrotropin levels and electroencephalographic activity in man

Plasma thyrotropin (TSH) levels have been previously shown to be associated with the internal sleep structure determined by conventional scoring of sleep stages. This temporal relationship was re-evaluated using spectral analysis of the sleep electroencephalogram (EEG). Eight healthy male subjects underwent two randomized night studies after having received either placebo or 5 mg ritanserin, a selective 5-HT2 receptor antagonist known to increase slow-wave sleep. Delta relative power and TSH levels, determined at 10 min intervals, were found to be inversely related with an average cross-correlation coefficient highly significant (P < 0.0001) in both experimental conditions. Alpha slow-wave index, an estimator of awakenings, and TSH pulses exhibited a significant temporal association in both conditions. These results demonstrate that TSH fluctuations are linked to the sleep EEG activity in man.

Slow wave electroencephalic activity parallels renin oscillations during sleep in humans

Previous studies have demonstrated that the nocturnal oscillations of plasma renin activity (PRA) exactly reflect rapid eye movement (REM) non-REM (NREM) sleep alternation with levels of PRA that increase during NREM sleep and decrease during REM sleep. These studies were based exclusively on conventional scoring of sleep stages. In the present study, we used spectral analysis of the sleep EEG to determine the variations in the different EEG frequency bands, together with PRA profiles. Eight male volunteers participated in a 1 night study. They were subjected to 8 h polysomnography including spectral analysis of the EEG, and to blood sampling every 10 min. Delta relative power and Sleep Intensity Index and PRA oscillations ran parallel in all individuals. An increase in slow waves was associated with an increase in PRA, whereas a decrease was associated with a decrease in PRA. Cross-correlation coefficients were significant and ranged between 0.34 and 0.74. Conversely, theta, alpha and beta bands and the EEG mean frequency were inversely proportional to PRA, with lower cross-correlation coefficients. These results may give further support to the hypothesis of a common mechanism controlling both SWA and renin release from the kidney.

Temporal relationship between prolactin secretion and slow-wave electroencephalic activity during sleep

It is well established that plasma prolactin (PRL) concentrations exhibit a sleep-dependent pattern, with the highest levels occurring during sleep and the lowest during waking. Still, controversy exists concerning an association between rapid eye movement (REM) and non-REM sleep cycles and plasma PRL pulses. These studies were all based on conventional scoring of sleep stages. In the present study, plasma PRL concentrations were analyzed at 10-minute intervals in 10 subjects during the night when sleeping. PRL secretory rates were calculated by a deconvolution procedure. Spectral parameters of sleep electroencephalographic (EEG) recordings were analyzed together with PRL secretion using cross-correlation. Slow-wave activity of the EEG and PRL secretion ran parallel in all individuals. Conversely, alpha and beta bands and the EEG mean frequency were inversely proportional to PRL secretion. In 9 of the 10 subjects studied, PRL secretion was concomitant with delta waves or lagged behind by 10-20 minutes, depending on subjects, with maximum cross-correlation coefficients ranging between 0.40 and 0.67. This temporal relationship between PRL secretion and delta waves was further assessed by a pulse-by-pulse analysis based on the calculation of probability levels after computer simulations. Nine of the 10 subjects displayed significant concomitance between delta wave activity and PRL secretory oscillations. These results demonstrate that PRL secretion during sleep is coupled to delta waves in young healthy men.