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

Selective alterations of the first NREM sleep cycle in humans by a dopamine D1 receptor antagonist (NNC-687)

This paper details the first study of the effects of dopamine D1 receptor antagonism on the regulation of human sleep EEG (electroencephalogram). The investigational drug NNC-687 (NNC 01-0687/CEE 03-310) was administered to 20 healthy young men in doses of 5, 10, and 15 mg in a double blinded, placebo controlled, crossover design. In rats, dopamine D1 receptor antagonism can produce large increases in the amounts of both rapid eye-movement (REM) and non-rapid eye-movement (NREM) sleep. In this study, drug effects were most prominent in the first NREM period. D1 antagonism markedly reduced the peak-amplitude of delta EEG waves but increased their instantaneous frequency as well as enhancing the total number, incidence, and burst-duration of sleep spindles. The length of the first NREM period was increased up to 47% over baseline. Despite these large increases in NREM sleep time, the amount of delta EEG power accumulated over the first NREM period was conserved at baseline levels. We note that the sleep-EEG profile of D1 antagonism is very similar to that of GABAA (gamma-aminobutyric acid) receptor modulators and suggest that D1 antagonism may alter the properties of the neuronal networks which generate delta and spindle, and K-complex EEG waveforms through the upstream modulation of GABAA receptor activity.

The relationship of alpha and delta EEG frequencies to pain and mood in 'fibrositis' patients treated with chlorpromazine and L-tryptophan

Aspects of sleep stage evaluation and analysis of alpha and delta EEG frequencies in sleep were shown to be related to musculo-skeletal pain and mood disturbance in patients with 'fibrositis syndrome'. Patients were treated at bedtime for 3 weeks with either chlorpromazine, 100 mg (8 patients), or L-tryptophan, 5 g (7 patients). Chlorpromazine, but not L-tryptophan, was associated with increased slow wave sleep and amelioration of pain and mood symptoms. Mean percent time/min or mean percent power/min of alpha frequency during NREM and REM sleep corrlated with overnight increase in pain measures, hostility, and decrease in energy. On the other hand, mean percent time/min of delta in NREM sleep was related to overnight decrease in pain and mean percent delta power/min was associated with decreased anxiety and hostility, and increased energy.

The effect of oxazepam on sleep in normal human volunteers

The effects of 25 mg of oxazepam, a benzodiazepine with a short half-life and no active metabolites, were compared with placebo in two healthy volunteers in a single-blind polygraphically recorded sleep study. The experiment lasted for 24 nights and recordings were made for 11 nights. It was found that 25 mg oxazepam induced sleep faster than placebo, and that the subjects awoke less often during the treatment period. The total amount of REM-sleep was not affected. However, REM-sleep was shortened during the first part of the night and extended during the latter part of the night. Slow-wave sleep diminished differently in the two subjects, possibly due to interindividual differences in the rate of elimination of oxazepam. The effect on blood pressure was small, and the normal physiological difference between bedtime and morning blood pressure was preserved.

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.