Effects of three Benzodiazepines (Nitrazepam, Flunitrazepam and Bromazepam) on Sleep of Normal Subjects, Studied with an Automatic Sleep Scoring System

The influence of oxytocin-based interventions on sleep-wake and sleep-related behaviour and neurobiology: A systematic review of preclinical and clinical studies

The oxytocin (OXT) system has garnered considerable interest due to its influence on diverse behaviours. However, scant research has considered the influence of oxytocin on sleep-wake and sleep-related behaviour and neurobiology. Consequently, the objective of this systematic review was to assess the extant preclinical and clinical evidence for the influence of oxytocin-based interventions on sleep-wake outcomes. The primary search was conducted on 22/7/2020 using six electronic databases; 30 studies (19 preclinical, 11 clinical) were included based on inclusion criteria. Studies were evaluated for risk of bias using the SYRCLE tool and the Cochrane risk of bias tools for preclinical and clinical studies, respectively. Results indicated manipulation of the OXT system can influence sleep-wake outcomes. Preclinical evidence suggests a wake-promoting influence of OXT system activation whereas the clinical evidence suggests little or no sleep-promoting influence of OXT. OXT dose was identified as a likely modulatory factor of OXT-induced effects on sleep-wake behaviour. Future studies are necessary to validate and strengthen these tentative conclusions about the influence of OXT on sleep-wake behaviour.

Stability of cognition across wakefulness and dreams in psychotic major depression

Cognitive bizarreness has been shown to be equally elevated in the dream and waking mentation of acutely symptomatic inpatients diagnosed with affective and non-affective psychoses. Although some studies have reported on dream content in non-psychotic depression, no study has previously measured this formal aspect of cognition in patients hospitalized for Psychotic Major Depression (PMD). Sixty-five dreams and 154 waking fantasy reports were collected from 11 PMD inpatients and 11 age- and sex-matched healthy controls. All narrative reports were scored by judges blind to diagnosis in terms of formal aspects of cognition (Bizarreness). Dream content was also scored (Hall/Van de Castle scoring system). Unlike controls, PMD patients had similar levels of cognitive bizarreness in their dream and waking mentation. Dreams of PMD patients also differed from those of controls in terms of content variables. In particular, Happiness, Apprehension and Dynamism were found to differ between the two groups. Whereas dream content reflects a sharp discontinuity with the depressive state, cognitive bizarreness adequately measures the stability of cognition across dreams and wakefulness in PMD inpatients.

Gamma-aminobutyric acid (GABA) receptor mediates suanzaorentang, a traditional Chinese herb remedy, -induced sleep alteration

The sedative-hypnotic medications, including benzodiazepines and non-benzodiazepines, are the most common treatments for insomnia. However, concerns regarding patterns of inappropriate use, dependence and adverse effects have led to caution in prescribing those sedative-hypnotic medications. On the other hand, a traditional Chinese herb remedy, suanzaorentang, has been efficiently and widely used in clinic for insomnia relief without severe side effects in Asia. Although suanzaorentang has been reported to improve sleep disruption in insomniac patients, its mechanism is still unclear. The present study was designed to elucidate the effects of oral administration of suanzaorentang on physiological sleep-wake architectures and its underlying mechanism in rats. We found that oral administration of suanzaorentang at the beginning of the dark onset dose-dependently increased non-rapid eye movement sleep (NREMS) during the dark period, but had no significant effect on rapid eye movement sleep (REMS). Our results also indicated that intracerebroventricular (ICV) administration of gamma-aminobutyric acid (GABA) receptor type A antagonist, bicuculline, significantly blocked suanzaorentang-induced enhancement in NREMS during the dark period, but GABA(B) receptor antagonist, 2-hydroxysaclofen had no effect. These results implicated that this traditional Chinese herb remedy, suanzaorentang increases spontaneous sleep activity and its effects may be mediated through the GABA(A) receptors, but not GABA(B) receptors.

Effects of ramelteon (TAK-375) on nocturnal sleep in freely moving monkeys

We investigated the effects of (S)-N-[2-(1,6,7,8-tetrahydro-2H-indeno-[5,4]furan-8-yl)ethyl]propionamide (ramelteon, TAK-375), a novel MT1/MT2 receptor agonist, on nocturnal sleep in freely moving monkeys and compared these results with those of melatonin and zolpidem. Treatment with ramelteon (0.03 and 0.3 mg/kg, p.o.) significantly shortened latency to sleep onset and significantly increased total duration of sleep. Treatment with melatonin (0.3, 1, and 3 mg/kg, p.o.) also decreased sleep latency, but the effect was weak; the only significant reduction was seen with the 0.3 mg/kg dose on latency to light sleep. Melatonin had no significant effects on the duration of sleep. Zolpidem had no significant effects on latency to sleep onset in this study at any dose (1, 3, 10, and 30 mg/kg, p.o.). The highest dose (30 mg/kg) of zolpidem had a tendency to increase slow wave sleep; however, it also induced apparent sedation and myorelaxation. Treatment with ramelteon and melatonin had no evident effect on the general behavior of the monkeys. Spectral analysis (fast Fourier transform, FFT) of both ramelteon and melatonin revealed sleep patterns that were indistinguishable from those of naturally occurring sleep. The EEG power spectra of zolpidem were qualitatively different from that of naturally occurring physiological sleep. Results of the present study support the investigation of ramelteon as a sleep-promoting agent in humans.

Brain inhibitory mechanisms involved in basic and higher integrated sleep processes

Brain function is supported by central activating processes that are significant during waking, decrease during slow wave sleep following waking and increase again during paradoxical sleep during which brain activation is as high as, or higher than, during waking in nearly all structures. However, inhibitory mechanisms are crucial for sleep onset. They were first identified by behavioral, neuroanatomical and electrophysiological criteria, then by pharmacological and neurochemical ones. During slow wave sleep, they are supported by GABAergic mechanisms located at midbrain, mesopontine and pontine levels but are induced and sustained by forebrain and hindbrain influences. GABAergic processes are also responsible for paradoxical sleep occurrence, particularly by suppression of noradrenaline and serotonin (5-HT) inhibition of paradoxical sleep-generating structures. Hindbrain and forebrain modulate these structures situated at the mesopontine level. For sleep mentation, the noradrenergic and serotonergic silence is thought, today, to be directly, or indirectly, responsible for dopamine predominance and glutamate decrease in the nucleus accumbens, which could be the background of the well-known psychotic-like mental activity of dreaming.

GABA mechanisms and sleep

GABA is the main inhibitory neurotransmitter of the CNS. It is well established that activation of GABA(A) receptors favors sleep. Three generations of hypnotics are based on these GABA(A) receptor-mediated inhibitory processes. The first and second generation of hypnotics (barbiturates and benzodiazepines respectively) decrease waking, increase slow-wave sleep and enhance the intermediate stage situated between slow-wave sleep and paradoxical sleep, at the expense of this last sleep stage. The third generation of hypnotics (imidazopyridines and cyclopyrrolones) act similarly on waking and slow-wave sleep but the slight decrease of paradoxical sleep during the first hours does not result from an increase of the intermediate stage. It has been shown that GABA(B) receptor antagonists increase brain-activated behavioral states (waking and paradoxical sleep: dreaming stage). Recently, a specific GABA(C) receptor antagonist was synthesized and found by i.c.v. infusion to increase waking at the expense of slow-wave sleep and paradoxical sleep. Since the sensitivity of GABA(C) receptors for GABA is higher than that of GABA(A) and GABA(B) receptors, GABA(C) receptor agonists and antagonists, when available for clinical practice, could open up a new era for therapy of troubles such as insomnia, epilepsy and narcolepsy. They could possibly act at lower doses, with fewer side effects than currently used drugs. This paper reviews the influence of different kinds of molecules that affect sleep and waking by acting on GABA receptors.

Diazepam-induced changes in sleep: role of the alpha 1 GABA(A) receptor subtype

Ligands acting at the benzodiazepine (BZ) site of gamma-aminobutyric acid type A (GABA(A)) receptors currently are the most widely used hypnotics. BZs such as diazepam (Dz) potentiate GABA(A) receptor activation. To determine the GABA(A) receptor subtypes that mediate the hypnotic action of Dz wild-type mice and mice that harbor Dz-insensitive alpha1 GABA(A) receptors [alpha1 (H101R) mice] were compared. Sleep latency and the amount of sleep after Dz treatment were not affected by the point mutation. An initial reduction of rapid eye movement (REM) sleep also occurred equally in both genotypes. Furthermore, the Dz-induced changes in the sleep and waking electroencephalogram (EEG) spectra, the increase in power density above 21 Hz in non-REM sleep and waking, and the suppression of slow-wave activity (SWA; EEG power in the 0.75- to 4.0-Hz band) in non-REM sleep were present in both genotypes. Surprisingly, these effects were even more pronounced in alpha1(H101R) mice and sleep continuity was enhanced by Dz only in the mutants. Interestingly, Dz did not affect the initial surge of SWA at the transitions to sleep, indicating that the SWA-generating mechanisms are not impaired by the BZ. We conclude that the REM sleep inhibiting action of Dz and its effect on the EEG spectra in sleep and waking are mediated by GABA(A) receptors other than alpha1, i.e., alpha2, alpha3, or alpha5 GABA(A) receptors. Because alpha1 GABA(A) receptors mediate the sedative action of Dz, our results provide evidence that the hypnotic effect of Dz and its EEG "fingerprint" can be dissociated from its sedative action.

Effects of hypnotics on the sleep EEG of healthy young adults: new data and psychopharmacologic implications

Benzodiazepine hypnotics increase NREM sleep and alter its EEG by reducing delta (0.3-3 Hz) and increasing sigma (12-15 Hz) and beta (15-23 Hz) activity. We tested whether the nonbenzodiazepine hypnotic, zolpidem (10 mg), produced the same pattern of sleep and EEG changes as two "classical" benzodiazepines, triazolam (0.25 mg) and temazepam (30 mg). Sleep EEG of 16 subjects was analyzed with period amplitude analysis for 3 nights during drug administration or placebo. The effects of zolpidem were in the same direction but generally of smaller magnitude than those of the classical benzodiazepines. These differences are more likely the result of non-equivalent dosages than different pharmacologic actions. Period amplitude analysis showed that the decreased delta activity resulted mainly from a decrease in wave amplitude. In contrast, the increased sigma and beta activity were produced by increased wave incidence. Delta suppression increased with repeated drug administration but sigma and beta stimulation did not. While these findings have little relevance for the clinical choice of hypnotics they may hold important implications for the brain mechanisms involved in hypnotic tolerance and withdrawal delirium.

Independence of sleep EEG responses to GABAergic hypnotics: biological implications

GABAergic hypnotics are known to depress non-rapid eye movement delta and rapid eye movements and to stimulate non-rapid eye movement sigma (spindles) and beta EEG. This study addressed the question of whether the magnitudes of these effects are significantly correlated. Data were from a study in 16 normal subjects whose sleep was recorded for five nights under placebo and for three nights each under zolpidem (10 mg), triazolam (0.25 mg) and temazepam (30 mg). EEG was analyzed with both period-amplitude and power spectral (FFT) analysis. The magnitudes of the EEG and eye movement density responses were not significantly correlated for any of the three drugs. It is therefore unlikely that sleep responses to GABAergic drugs can be explained by the common cellular action (increased chloride conductance) of these drugs. We suggest that the sleep EEG responses are manifestations of complex (but consistent) interactions of excitation and inhibition in large brain systems although certain aspects of these responses (e.g. the different time courses of delta vs sigma and eye movement responses) may reflect molecular adaptations. A separate observation in this study was the strong traitlike characteristics of the sleep variables studied. These variables were highly correlated across nights of baseline sleep; in addition, individual differences in baseline sleep were significantly retained on the third night of temazepam administration.

Benzodiazepine effects on human sleep EEG spectra: a comparison of triazolam and flunitrazepam

The effects of 0.5 mg triazolam (TRI) and 4 mg flunitrazepam (FNZ) on the sleep electroencephalogram (EEG) were studied in eleven (six for TRI, and five for FNZ) healthy young male subjects. C3 EEG channel data of one baseline night, three drug nights and two withdrawal nights were recorded and their analyzed using a fast Fourier transformation (FFT) method. Changes in the 0.5 Hz to 40 Hz power spectrum showed that: 1) both TRI and FNZ increased higher frequency activity and reduced lower frequency activity on the drug nights; 2) on drug nights, NREM sigma frequency power was more strongly enhanced by TRI than FNZ, while the beta power of both NREM and REM was more strongly enhanced by FNZ than TRI; 3) NREM alpha power increased on the second night of withdrawal from both TRI and FNZ; 4) the power spectra for both NREM and REM sleep returned to baseline levels by the fourth night of withdrawal from either TRI or FNZ. These findings suggest that 0.5 mg TRI and 4 mg FNZ have both common and differing pharmacological effects on the central nervous system. Such differences could be caused by differences in the dose, half-life or systemic distribution of these two drugs.

Effect of the GABA uptake inhibitor tiagabine on sleep and EEG power spectra in the rat

1. The sleep profiles induced by agonists and agonistic modulators of gamma-aminobutyric acidA (GABA[A]) receptors differ markedly. With regard to GABA(A) agonists, the effects may be due to the fact that these agents are poor substrates for uptake and are therefore likely to activate GABA(A) receptors tonically. To investigate this possibility, we assessed the sleep effects of two doses (2 and 10 mg kg[-1]) of the GABA re-uptake inhibitor tiagabine, administered intraperitoneally at light onset in 8 rats. Electroencephalogram (EEG) and electromyogram were recorded during the first 8 h after the injection. 2. Compared with vehicle, tiagabine had minimal effects on the temporal pattern of non-rapid eye movement sleep (non-REMS) and on the total time spent therein. However, tiagabine dose-dependently elevated EEG activity during non-REMs, most prominently in the lower frequencies (1-8 Hz) and least pronounced in the frequencies between 11 and 16 Hz. During the first 2 h after the injection, 10 mg kg(-1) tiagabine elicited repetitive episodes of hypersynchronous EEG waves during wakefulness and slightly suppressed REMS. Except for these effects, tiagabine hardly influenced the time spent in and EEG activity during wakefulness and REMS. 3. The effects of tiagabine on state-specific EEG activity were qualitatively very similar to those elicited by GABA(A) agonists. These findings support the hypothesis that the influence of GABA(A) agonists on EEG signals may be caused by tonic stimulation of GABA(A) receptors.

The intermediate stage and paradoxical sleep in the rat: influence of three generations of hypnotics

Paradoxical sleep in the rat, cat and mouse is preceded and sometimes followed by a short-lasting intermediate stage characterized by high-amplitude anterior cortex spindles and low-frequency hippocampal theta rhythm. Several neurophysiological arguments suggest that the intermediate stage corresponds to a brief functional disconnection of the forebrain from the brainstem. This paper is devoted to the review of quantitative and qualitative influences of three generations of hypnotics on the intermediate stage-paradoxical sleep couple. Barbiturates, first-generation hypnotics, extend the intermediate stage at the expense of paradoxical sleep. Three benzodiazepines are compared, two with a short half-life (triazolam and midazolam) and one with a long half-life (diazepam). They also decrease sleep occurrence latency and increase the intermediate stage at the expense of paradoxical sleep, except for midazolam, which increases both the intermediate stage and paradoxical sleep at low dose. Zolpidem and zopiclone, hypnotics of third generation, decrease paradoxical sleep but the intermediate stage never substitutes for paradoxical sleep. The results are discussed in relationship to the functional aspects of this turning-point period of sleep.

Improvement of hypertonus after treatment for sleep disturbances in three patients with severe brain damage

Treatment for sleep disturbance was given to three patients with severe brain damage (a 14-year-old boy, an 8-year-old girl and a 9-year-old boy), and changes in their muscle tone were estimated using F-wave analysis. In all patients, F-wave analysis was performed in the ulnar nerve before and 2 weeks after treatment with flunitrazepam or melatonin. From 16 recordings of F-waves, the mean amplitude and latency, the ratio of F-wave amplitude to M-wave amplitude (F/M ratio), the mean F-wave conduction velocity and the F-wave occurrence were evaluated. All patients showed at least one significant decrement of mean F-wave amplitude, the F-wave occurrence and mean F/M ratio, which suggests a reduction in muscle tone after treatment for sleep disturbance. It is concluded that treatment for sleep disturbance occurring in brain damage is important in view of the improvement of increased muscle tone.

Muscimol and midazolam do not potentiate each other's effects on sleep EEG in the rat

The interaction of a gamma-aminobutyric acid-A (GABAA) receptor agonist and a benzodiazepine-type modulator of GABAA receptors on sleep was investigated. Low doses of muscimol (0.3 mg/kg) and the benzodiazepine midazolam (1.5 mg/kg) were administered alone and in combination, in random order, to eight rats. All injections were given intraperitoneally at light onset. Electroencephalogram (EEG) and electromyogram were recorded during the first 6 h post injection. Compared with vehicle, muscimol hardly affected the time spent in non-rapid eye movement sleep (non-REMS) and REMS, but significantly enhanced EEG activity in the frequency range between 2 and 6 Hz during non-REMS. Midazolam significantly increased the time spent in non-REMS, reduced EEG activity at frequencies < 12 Hz, and elevated EEG activity in most higher frequencies during this state. The combined administration of muscimol and midazolam affected non-REMS-specific EEG activity in an unexpected fashion: the effects were intermediate between those of muscimol and midazolam. These results indicate that muscimol and midazolam have dissimilar effects on EEG within non-REMS and demonstrate that midazolam does not augment but attenuates the muscimol-induced changes in sleep EEG. Our data are at variance with established mechanisms, according to which agonistic modulators would have similar effects and should potentiate the effects of GABAA agonists. The present data suggest that application of agonists and agonistic modulators of GABAA receptors causes differential net effects on sleep parameters.

Flunitrazepam effects on human sleep EEG spectra: Differences in NREM, REM and individual responses

Flunitrazepam (FNZ) (4mg), an intermediate type benzodiazepine (BDZ) hypnotic, was administered orally to five healthy male subjects (Ss) for seven consecutive nights. Sleep EEG from the baseline night (BLN), the initial drug night (IDN), the fourth and the seventh drug nights (4DN, 7DN) was subjected to fast Fourier transform (FFT) analysis. During NREM sleep of 4DN and 7DN the sigma band (11.0-12.5 Hz) activity was similarly enhanced in every S. In REM of 4DN and 7DN beta band (23.0-29.0 Hz) was enhanced, but with larger variations among Ss. High intra-individual consistency of the relative EEG power patterns on 4DN and 7DN was observed. These results suggest that 1) EEG responses to FNZ are different in sleep states; explorations of these differences may provide better understandings of sleep mechanisms, and 2) individual variations in EEG responses may reflect individual variations of the BDZ receptor system. These methods may be useful for exploring receptor changes in neuropsychiatric disorders.

Melatonin effect on daytime sleep in men: suppression of EEG low frequency activity and enhancement of spindle frequency activity

The effect of melatonin (5 mg, p.o.) on electroencephalographic (EEG) activity during sleep was investigated in eight men in a placebo-controlled cross-over design. Melatonin was administered immediately prior to a 4-h daytime sleep episode (13-17 h) after a partial sleep deprivation. The non-REM sleep stages and REM sleep duration were not significantly affected. Melatonin enhanced EEG power density in non-REM sleep in the 13.75-14.0 Hz bin (i.e., within the frequency range of sleep spindles), and reduced activity in the 15.25-16.5 Hz band. In the first 2 h spectral values within the 2.25-5.0 Hz range were reduced. These changes in the EEG are to some extent similar to those induced by benzodiazepine hypnotics and to the contribution of the endogenous circadian pacemaker to the spectral composition of the sleep EEG when sleep occurs at night.

Benzodiazepines promote the intermediate stage at the expense of paradoxical sleep in the rat

The effects of diazepam, a long half-life benzodiazepine, midazolam and triazolam, two with short half-life, on the transitional stage between deep slow wave sleep and paradoxical sleep were studied in Wistar and WAG/Rij rats. This intermediate stage is characterized by the unusual association of cortical spindles and low frequency hippocampal theta rhythm. The main result was extension of the intermediate stage at the expense of paradoxical sleep by diazepam and triazolam by influencing only the duration of the intermediate stage and both the onset and maintenance of paradoxical sleep. Midazolam increased both intermediate stage and paradoxical sleep. Several differences in the qualitative modulation of the stage characteristics and between rat strains were found. In regard to the possible peculiar physiological significance of the intermediate stage, we conclude that benzodiazepines promote a transient pharmacological cerveau isolé-like stage during sleep in rats.

Pregnenolone enhances EEG delta activity during non-rapid eye movement sleep in the rat, in contrast to midazolam

Several endogenous steroids exert their neuroactivity through non-genomic effects and act as potent GABAA receptor-agonists or-antagonists. To examine the influence of the main precursor of these steroids on sleep-wake behaviour, pregnenolone (400 micrograms) was dissolved in oil and administrated s.c. to 8 rats at the beginning of the light period. For comparison, the benzodiazepine midazolam was also injected (3 mg/kg). The effects on the amounts of the vigilance states and on the EEG signals within each state were investigated during 24 hours. Compared to control vehicle, pregnenolone did not significantly affect the duration of the vigilance states. However, delta activity (0.5-4 Hz) within non-rapid eye movement sleep (nonREMS) was enhanced throughout the recording period. Midazolam increased nonREMS, decreased wakefulness and, transiently, also suppressed rapid eye movement sleep (REMS). Spectral analysis of the EEG within nonREMS showed a long lasting reduction in delta and theta activity (4-9 Hz) and a shorter lasting enhancement in the higher frequencies (10-25 Hz). EEG activity within REMS and wakefulness was elevated in the higher frequencies (> or = 10 Hz) during the the first half of the recording period. We conclude that in the rat, the effects of midazolam on EEG activity closely resemble those of benzodiazepines in other mammalian species. The influence of pregnenolone on EEG delta activity within nonREMS indicates that pregnenolone acts as an inverse GABAA-benzodiazepine agonist.

Neurosteroid pregnenolone induces sleep-EEG changes in man compatible with inverse agonistic GABAA-receptor modulation

The steroid pregnenolone (P) and its sulfate (PS) can accumulate in the central nervous system independent of peripheral sources. Pharmacologically, the sulphated form of P interacts with the GABAA receptor complex, and functional assays show that this steroid behaves as an allosteric GABAA receptor antagonist. The present study explored the effect of a single dose of P upon the sleep-EEG and concurrent secretion of growth hormone and cortisol in male volunteers. P increased the amount of time spent in slow wave sleep and depressed EEG sigma power. Sleep-associated nocturnal cortisol and growth hormone secretion remained unchanged, ruling out the possibility that P exerted its effect via altered regulation of these hormones. Furthermore, results from in vitro studies on the potency of P to activate gene transcription via corticosteroid receptors made a genomic action of P via hormone receptor-sensitive DNA sequences unlikely. We conclude that P acts in a non-genomic fashion at or in the vicinity of the benzodiazepine binding site, modulating allosterically the GABAA receptor like a partial inverse.

Effects of zopiclone, flunitrazepam, triazolam and levomepromazine on the transient change in sleep-wake schedule: polygraphic study, and the evaluation of sleep and daytime condition

1. The effects of zopiclone 10mg (ZP), flunitrazepam 1mg (FN), triazolam 0.25mg (TZ) and levomepromazine 5mg (LP) on two models of sleep-wake schedule change-6 hours advanced shift: (A-shift), and 6 hours delayed: (D-shift)--were investigated in 6 healthy volunteers using polysomnography. 2. In A-shift with placebo, TST, SEI, %SR and REM/NREM decreased. ZP, FN and TZ shortened SL. All drugs increased TST and SEI. TZ and LP increased %SR and REM/NREM. 3. In D-shift with placebo, TST decreased, SWSL was prolonged, %S3+4 decreased, and %SR and REM/NREM increased. All drugs increased TST. ZP and LP shortened SWSL. All drugs increased %SWS. ZP, FN and TZ decreased %SR. ZP and FN decreased REM/NREM. 4. Daytime mental and physical conditions were worse than usual on more than half of the days in A- and D-shift. LP and FN caused some inadequate conditions on the following days. Significantly higher REM/NREM was observed in the nights before the days with worse mental conditions in D-shift, and lower REM/NREM in the nights before the days with worse physical conditions in A-shift. 5. It is concluded that TZ and ZP are superior to the others for A-shift and D-shift, respectively.

Effects of ritanserin and chlordiazepoxide on sleep-wakefulness alterations in rats following chronic cocaine treatment

The effects of ritanserin, a 5-hydroxytryptamine-2 (5-HT2) receptor antagonist, and chlordiazepoxide, a benzodiazepine agonist, on sleep-wakefulness disturbances in rats after acute administration of cocaine and after discontinuation of chronic cocaine treatment were examined. Intraperitoneal (IP) injection of chlordiazepoxide (10 mg/kg) but not ritanserin (0.63 mg/kg) prevented the increase of wakefulness (W) and the reduction of light slow wave sleep (SWS1) and deep slow wave sleep (SWS2) induced by an acute injection of cocaine (20 mg/kg IP). Daily injection of cocaine (20 mg/kg for 5 days, then 30 mg/kg for 5 days IP) at the onset of the light phase elicited an increase of W and a concomitant decrease of SWS1, SWS2 and paradoxical sleep (PS) in the light phase, followed by a rebound in SWS2 and PS in the subsequent dark phase. Following cocaine discontinuation, the circadian distribution of sleep-wakefulness states remained disturbed in saline-treated rats for at least 5 days. Both ritanserin (0.63 mg/kg IP/day) and chlordiazepoxide (10 mg/kg IP/day) reduced the alteration in the distribution of W and SWS2 throughout the light-dark cycle from the first day of administration on, but failed to prevent PS alterations. The mechanisms by which both compounds exert their effect are probably quite different. For chlordiazepoxide sedative and sleep-inducing properties probably play a major role. In contrast, for ritanserin SWS2-increasing properties and its ability to reverse preference for drugs of abuse without inducing aversion might be key factors.

Ultradian dynamics of sleep after a single dose of benzodiazepine hypnotics

A single bedtime dose of the benzodiazepine hypnotics, flunitrazepam (2 mg), triazolam (0.5 mg) or flurazepam (30 mg), was administered to young, healthy subjects. Abortive first rapid eye movement sleep (REMS) episodes, characterized by a low level of EEG slow-wave activity (spectral power density in the 0.75-4.5 Hz band) without rapid eye movements and/or muscle atonia, were more frequent in the drug night than in the placebo night or in the drug-free night following upon the drug night. The benzodiazepine hypnotics depressed slow-wave activity in non-REM sleep (NREMS) in the drug night and the subsequent drug-free night. However, the typical declining trend of slow-wave activity over the first three NREMS-REMS cycles, and the cyclic ultradian pattern of slow-wave activity were little affected by the hypnotics. The results indicate that benzodiazepine hypnotics depress the generation of slow EEG waves without disrupting the homeostatic and ultradian processes of sleep regulation.

Effect of zolpidem on sleep and sleep EEG spectra in healthy young men

A single 10 mg dose of zolpidem, an imidazopyridine hypnotic, was administered to young, healthy male volunteers prior to bedtime. The drug reduced REM sleep but did not significantly affect other sleep stages and subjective sleep parameters. All-night spectral analysis of the EEG revealed that power density in nonREM sleep was reduced in the low-frequency range (1.25-2.5 Hz; 5.25-10.0 Hz) and increased in the spindle frequency range (12.25-13.0 Hz). Significant changes in the EEG spectrum were present in the first 4 h of sleep. The pattern of the spectral changes was similar to those induced by other hypnotics that bind to the GABAA/benzodiazepine receptor complex. There were no residual effects of zolpidem on psychomotor performance in the morning, on the self-rated state in the morning and at noon, and on sleep and EEG parameters in the subsequent drug-free night.

Hypnotics and sleep physiology: a consensus report. European Sleep Research Society, Committee on Hypnotics and Sleep Physiology

The effects of hypnotics on descriptive and functional aspects of electrophysiological sleep parameters are assessed in this report. Because of the arbitrary definition of some of the criteria underlying the conventional sleep stage scoring procedure, computer-aided methods of EEG analysis have become increasingly important for recording and interpreting pharmacological effects on sleep. Of particular interest are the changes of EEG slow-wave activity, since this parameter varies as a function of prior sleep and waking. Several types of interaction between hypnotics and sleep regulation are discussed, some recent pharmacological developments are highlighted, and some common problems in clinical trials are specified.

Anterior-posterior relationships of EEG in photosensitive subjects: coherence and cross-phase-spectral analysis

Coherence and cross-phase-spectral analysis of EEG were applied to photo-sensitive subjects to investigate the mechanism of the generalization of photo-induced paroxysms. Coherence values were high between frontal (F) and central (C) in resting records and between F-C in EEGs revealing harmonic responses, where the coherence values of F-O (occipital) were also high, and the waves of F preceded those of O. In cases of occipital-localized 3/6 Hz (poly) spike-waves, discharges of O preceded those of F. During the stage of generalized paroxysms, discharges were highly cohered between all electrodes. Discharges of F preceded those of O, and appeared to play as a generator. Two conditions with clinical symptoms had higher frequencies (greater than or equal to 12 Hz) and shorter time lags (less than or equal to 5 msec) than conditions without symptoms.

Dose level effects of triazolam on sleep and response to a smoke detector alarm

Thirty-six young adult, male subjects with sleep-onset insomnia were equally divided into placebo, 0.25 mg, and 0.5 mg triazolam groups to examine the effects of the hypnotic, with particular attention to dose level on efficacy, sleep stages, and awakening to a smoke detector alarm. On nights 1 and 4 of a five-consecutive-night protocol, a standard home smoke detector alarm was sounded during stage 2, 5 min after sleep onset, in slow wave sleep (SWS), and at the time of the early morning awakening. The alarm registered 78 dB SPL at the pillow. EEG arousal latency and reaction time to a button press were studied. Failure to awaken to three 1-min alarm presentations was scored as "no response." Both dose levels produced similar reductions in sleep latency, decreases in SWS, increases in stage 2, and increases in sleep efficiency. Both dose levels showed similar sedative effects to the smoke alarm. Fifty percent of triazolam subjects failed to awaken on night 1 during SWS, and EEG arousal and response latencies were significantly slowed. Some drug tolerance or sensitization to the alarm was seen by night 4. By morning, all subjects were easily awakened on both nights. The 0.25 mg dose is clearly an effective dose level for both sleep efficacy and sedative effects to outside noise, which in some instances could pose potential problems.

Serotonergic involvement in pharmacological action of the anxiolytic-sedatives thalidomide and supidimide

The anxiolytic-sedative drugs thalidomide and supidimide inhibited spontaneous motor activity in rats. Both compounds inhibited the serotonin (5-HT) behavioural syndrome induced by tranylcypromine (TCP) plus L-tryptophan (TRP) or clorgyline plus the selective 5-HT uptake blocker, LM 5008 (4-[2-(3-indolyl)ethyl]piperidine) and delayed the behavioural effects of p-chloro-amphetamine, a releaser of 5-HT. The behavioural syndrome induced by the 5-HT agonist, 5-methoxy-N,N'-dimethyltryptamine (5-MeODMT) was unaffected by supidimide pretreatment. Thus supidimide does not possess 5-HT receptor antagonistic properties. This was further substantiated by the unaltered 5-HT-induced platelet aggregation in the presence of supidimide (10(-7)-10(-4) M). A decrease of 5-HT release into the synaptic cleft will lead to a diminished behavioural response to drugs that act presynaptically. Supidimide induced a greater increase in accumulation of brain 5-HT in TCP (5 mg/kg) plus TRP (100 mg/kg)-treated animals as compared to that in the corresponding controls. These data indicate that the behavioural and pharmacological actions of supidimide may be related to its inhibition of 5-HT release.

Temazepam and the perceptual-motor performance of professional footballers

The use of benzodiazepines to overcome the possible debilitating effects of travel on football performance is a recent phenomenon and indicative of current usage of such drugs. Contemporary psychological theory is critical of many of the measures used to monitor such drugs. This study has created a battery of tests which include some measures which are deemed more ecologically valid and, for purposes of comparison, some traditional indices. On a sample of First Division professional Association footballers temazepam (40 mg) was compared with placebo on these measures and testing occurred on the afternoon following night time medication. The findings suggest that on such a protocol, perceptual-motor performance is not impaired.

Sleep spindle and delta changes during chronic use of a short-acting and a long-acting benzodiazepine hypnotic

Twenty-one medically screened insomniacs were studied over 59 nights in a double-blind, parallel groups design study. The 7 patients receiving a short-acting (triazolam) and the 7 receiving a long-acting (flurazepam) benzodiazepine hypnotic showed a similar pattern and magnitude of sleep EEG changes, especially during the latter part of the 37-night treatment period. Both groups significantly increased sleep spindle rate and decreased delta count per minute. The patterns of withdrawal were also similar. Plasma levels of N-desalkylflurazepam were not significantly related to the magnitude of EEG changes.

Effect of the benzodiazepine antagonist Ro 15-1788 on flunitrazepam-induced sleep changes

1 The modifications of human sleep induced by benzodiazepines, and particularly by flunitrazepam, are complex. Stage 4 and paradoxical sleep are both decreased; however, these two effects have a different evolution during and after single or short-term drug administration. 2 The benzodiazepine antagonist Ro 15-1788 also tends to depress stage 4, but with immediate recovery in the post-drug night, and does not modify paradoxical sleep. 3 In combined administration, this drug totally reverses the hypnogenic effect of flunitrazepam, as well as its effect on paradoxical sleep but not the decrease of slow wave sleep. 4 Some of the benzodiazepine-induced alterations of sleep may be related to receptors different from central benzodiazepine receptors, or to mechanisms not directly connected to this type of receptors.

Effect of a short-acting benzodiazepine on brain electrical activity during sleep

The effects of the short-acting benzodiazepine, triazolam, on EEG activity during sleep were assessed in poor sleepers. Twenty male subjects, mean age 21 +/- 2.37 years, participated. A screening night preceded 3 placebo nights, 6 treatment nights, and 2 placebo-withdrawal nights. During treatment, 10 subjects received triazolam (0.5 mg) and 10 received placebo. The treatment condition was double-blind. In addition to rate/min spindle count and number of delta half-waves/min, the auditory evoked response (AEP) was obtained on the last placebo baseline and the fifth drug night. Subjects receiving triazolam showed a significant increase in sleep spindles and a significant decrease in delta count during drug administration. Both values returned to baseline on the first withdrawal night. The AEP peak-to-trough amplitude was also significantly reduced during sleep by triazolam, but, as the time since drug ingestion increased, the amplitude of the AEP also increased. There was no difference in AEP amplitude between the two groups 5 h post-drug ingestion.

Quantitative analysis of training, sleep EEG and clinical response to EEG operant conditioning in epileptics

This report is a follow-up to a previous paper which described seizure rate changes with central cortical EEG feedback training in 8 poorly controlled epileptic subjects. Data examined here include associated training compliance and performance, sleep EEG spectra, clinical EEG and anticonvulsant blood levels. The study employed a double-cross-over, single blind ABA design applied to two subgroups of epileptic patients. Both groups had in common two training periods (A1, A2) in which either 12--15 c/sec (subgroup I, n = 4) or 18--23 c/sec (subgroup II, n = 4) was reinforced in the absence of 6--9 c/sec, movement or epileptiform discharge, and one training period (B) in which 6--9 c/sec was reinforced in the absence of 12--15 or 18--23 c/sec as well as movement and epileptiform discharge. Training periods occurred primarily in the home and lasted 3 months. Compliance with training instructions and response acquisition were demonstrated. Overall anticonvulsant blood levels were low and unrelated to EEG or seizure changes. Clinical EEG findings corresponded to sleep EEG and seizure rate outcomes. Power spectral analysis of sampled non-REM sleep from all-night EEG recordings obtained after each training phase indicated contingency specific changes which were limited to sensorimotor recordings in subgroup I and corresponded to the pattern of seizure rate changes in this group. EEG changes were also limited to sensorimotor cortex in subgroup II, but were linear and paralleled a progressive decrease in seizure rate. Both groups, however, showed the same pattern of EEG changes with seizure reductions; low and high frequencies were reduced and intermediate, rhythmic frequencies increased. Correlational analysis confirmed this relationship. The pattern, duration and topographic specificity of these changes suggested a normalization of sensorimotor EEG substrates related to the EEG feedback traning.

Changes in seizure susceptibility, sleep time and sleep spindles following thalamic and cerebellar lesions

The present experiment attempted to clarify conflicting evidence on the relationship of sleep spindles to seizure activation. Seizure thresholds were calculated in minutes post-injection following IP administration of the convulsant drug monomethylhydrazine (MMH) to cats with lesions intended to alter the occurrence of spontaneous 12-15 c/sec sleep spindles recorded from sensorimotor cortex. Twelve cats with bilateral cortical and subcortical recording electrodes were divided into 3 groups receiving electrolytic lesions in the dentate nucleus (group I), the ventrobasal (VB) thalamus (group II), or in one of various 'control' regions (group III). Lesion sites in group III animals avoided primary afferent pathways to VB thalamus, destruction of which has been found to enhance sleep spindle activity, and included cerebellar white matter and ventral pontine tegmentum. Prior to the MMH trials, baseline EEGs were obtained during pre- and post-lesion conditions. Following the MMH trial, lesions were verified histologically. Results of the MMH trial revealed that animals with dentate and ventrobasal thalamic lesions showed elevated seizure thresholds and slow wave sleep times relative to their own pre-lesion EEG baselines and to the pre- and post-lesion baselines of control animals. Furthermore, an increased incidence of sleep spindles was associated with dentate lesions while animals with ventrobasal thalamic lesions showed a shift in frequency from 8-11 c/sec to 12-15 c/sec activity during that state. These findings are compatible with the view that sleep spindles do not facilitate seizure activation and may, in fact, exert a protective influence.

Some aspects of the effects of clobazam on human psychomotor performance

1 Three studies are described, the first being a comparison of the effects of acute night-time doses of clobazam 20 mg, amylobarbitone sodium 100 mg, nitrazepam 5 mg and placebo, on choice reaction time, critical flicker fusion (CFF) and stabilometer performance. Clobazam improved early morning performance on a choice reaction test, in contrast to the other two active drugs. 2 Repeated doses of clobazam 10 mg three times daily, chlordiazepoxide 10 mg three times daily and diazepam 5 mg three times daily were given for 5 days. Again clobazam did not produce any impairment of psychomotor performance, and noticeably increased CFF thresholds. 3 The effects of an acute night-time dose of clobazam 20 mg on psychomotor performance the morning after night-time medication were correlated with the neuroticism scores (on the EPI) of the subjects. Clobazam exerts a differential effect on psychomotor performance dependent on the basic personality trait. 4 Clobazam seems to differ significantly from the 1,4-benzodiazepines in that, although it reduces anxiety, it does so without any apparent impairment of psychomotor performance.

Flurazepam effects on slow-wave sleep: stage 4 suppressed but number of delta waves constant

Repeated administration of flurazepam reduced stage 4 sleep (high delta-wave concentration) but produced a greater increase in stage 2 duration so that total sleep time was increased. Computer analysis revealed that the increased amount of stage 2 (low delta-wave concentration) sleep provided a number and duration of delta waves sufficient to offset the loss of delta activity in stage 4. However, the amplitude of the average delta wave was reduced. These results demonstrate the value of direct quantification of delta-wave activity, the variable that underlies visual classification of slow-wave sleep into stages 2 to 4. They also give rise to new hypotheses regarding the relative absence of side effects in spite of profound stage 4 suppression by flurazepam and the mechanisms by which total sleep time is increased by this drug.

A repeated dose comparison of three benzodiazepine derivative (nitrazepam, flurazepam and flunitrazepam) on subjective appraisals of sleep and measures of psychomotor performance the morning following night-time medication

Repeated doses of 5 mg nitrazepam, 15 mg flurazepam, and 1 mg flunitrazepam improved subjective assessments of the ease of getting to sleep and the perceived quality of induced sleep in a population of 30 healthy volunteers. The subjective reports of improved sleep inducement were related to a perceived difficulty in awakening from sleep the morning following medication. This subjectively reported "hangover" is also shown in the impairment of mental arithmetic abilities as measured on the serial subtraction of sevens technique. However, complex psychomotor performance is unaffected by repeated administration of these three benzodiazepine derivatives, although these later results are somewhat equivocal. Evidence of a "rebound phenomenon" following 4 nights' withdrawal of active medication is shown in both subjective and objective measures of sleep and early morning behaviour.

The effect of a new benzodiazepine on the polygraphically monitored sleep of normal volunteers

All-night sleep was polygraphically monitored from ten normal volunteers who took placebo and three dosage levels of a new benzodiazepine hypnotic, SCH 16134, in a double-blind, crossover design. All dosages of the drug decreased the time to fall asleep, and the two highest dosages also decreased interspersed wakefulness. REM sleep was suppressed, but slow-wave sleep was not affected in this experiment. The subjective quality of sleep was improved by the new hypnotic. One subject reported that he felt lethargic the day after the largest dose.

Automated sleep EEG analysis applied to the evaluation of drugs: illustration by study of clorazepate dipotassium

An automated sleep EEG analysis system was used to evaluate the effects of clorazepate dipotassium in normal subjects. Ten young-adult men slept 18 consecutive nights in the laboratory. On days 8-15 clorazepate (7.5 mg) was administered three times daily; on days 5-7 and 16-18 a placebo was administered in a similar fashion. The drug reduced amounts of alpha and delta activity and increased the amount of beta activity and the number of spindles. These effects generally persisted through the 3 day placebo recovery period. Our results suggest that sleep EEG waveform descriptors are sensitive indicators of drug activity and that beta activity in particular may be useful in the detailed description of various drug effects.

The effects of the sub-chronic administration of an anti-histamine, clemastine, on tests of car driving ability and psychomotor performance

A double-blind placebo-controlled crossover trial was carried out in 21 normal volunteers to study the effects of sub-chronic administration of clemastine on car driving ability and psychomotor performance. Subjects were assessed on 5 tests representing various aspects of everyday car driving experience, and on subjective rating scales for mood, sleep, and psychomotor integration. The results showed that repeated doses of 1 mg clemastine b.d. for 3 days had no significant consistent effect on any of the parameters measured.

Effect of flurazepam on sleep spindles and K-complexes

In this research, a quantitative study of the EEG from 5 subjects permitted a detailed analysis of the effect of 30 mg of flurazepam administered over 7 nights. Four placebo baseline nights and 3 placebo withdrawal nights were also recorded. For 4 of the subjects, a nondrug and nonplacebo follow-up record was obtained 4 to 6 weeks later. The subjects were 4 females, 1 male, age range 23-42. All complained of either sleep onset greater than 45 min, sleep length of less than 6 h, or two or more sleep awakenings. Compressed spectral analysis yielded a computer-generated somnogram on each of the 15 nights of sleep, and an automated spindle detector was used to count and measure the duration of spindle bursts with frequencies of 12.25-15.5 c/sec on baseline nights 3 and 4, drug nights 1, 2, 3 and 7, on the 3rd withdrawal night, and on the 4-6 week followup record. K-complexes were scored visually on the 4th baseline and 7th drug nights. There were no significant differences in spindle rate per minute among baseline nights and the follow-up record. By the 2nd drug night, spindle rate had significantly increased over the baseline rate. Linear contrast analysis indicated there was a significant increase of spindle rate over drug nights. All 5 subjects showed this pattern of increase. In contrast to the increase in spindle activity, the rate per minute of K-complexes significantly decreased during drug administration.

Residual effects of flunitrazepam

1 Twelve normal subjects were tested on a large battery of tests after a hypnotic dose of flunitrazepam(1 or 2 mg) and a placebo. Psychological tests were given 12 h after the drug and physiological tests 12, 15 and 18 h after the drug. 2 The tests included self-ratings of hypnotic effects and mood, the electroencephalogram, the auditory electroencephalographic evoked response, skin conductance, tapping, card-sorting and the symbol copying test. 3 Both doses of flunitrazepam were effective hypnotics according to the ratings, with an anxiolytic effect the following day. The EEG was significantly altered up to 18 h after the drug and the behavioural tests showed a motor impairment 12 h after drug administration. 4 Nearly all changes displayed linear dose-related trends.