1 The effect of N-desmethyldiazepam (nordiazepam, 5 and 10 mg) and potassium clorazepate (15 mg, a precursor of nordiazepam) on sleep was studied in six healthy adult males. Electroencephalography (EEG) was used for sleep measures, and analogue scales were used for subjective assessments of well-being and sleep quality. 2 Effects on total sleep time were limited to the night of ingestion. There were increases with nordiazepam (5 and 10 mg) (P = 0.05) and 0.001 respectively), and with clorazepate (15 mg) (P = 0.01). Sleep onset latencies were shortened, particularly with nordiazepam, and awakening to stage 0 activity was reduced, by both drugs. The latency to stage 3 was reduced by nordiazepam (5 and 10 mg) (P = 0.05). 3 There were no effects of nordiazepam (5 mg) on the duration (min) of sleep stages. Nordiazepam (10 mg) and clorazepate (15 mg) reduced the duration of stage 0 and stage 1, and there were increases in stage 2. Reduced stage 1 and increased stage 2 sleep were observed during the recovery night. No effects were observed with stage 3, but there was evidence that stage 4 activity was depressed on the recovery night only. No effects were observed on REM sleep, except that the appearnace of the first REM period was delayed with clorazepate (15 mg) P = 0.01). The effect of nordiazepam (10 mg) and clorazepate (15 mg) were comparable, and each modified sleep for about 28-30 h after ingestion. 4 With nordiazepam (10 mg) and clorazepate (15 mg) the subjects, as a group, reported improved sleep, but subjective assessments of well-being were not altered. Correlations were calculated for sleep measures and subjective assessments.

Adult↗

PubMed1975

Effect of mild hypoxia on delyaed differentiation in the monkey (Macaca mulatta).

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Altitude↗

PubMed1975

Comparison of the residual effects of two benzodiazepines (nitrazepam and flurazepam hydrochloride) and pentobarbitone sodium on human performance.

1 The residual effects of two benzodiazepines, nitrazepam (10 mg) and flurazepam hydrochloride (30 mg), and pentobarbitone sodium (200 mg) were studied by adaptive tracking and by reaction time. Performance was measured at 10 h, 13 h, 16 h, 19 h and 34 h after ingestion of each drug. Impaired performance on adaptive tracking was observed at 10 h, 13 h, 16 h and 19 h after nitrazepam and pentobarbitone sodium and at 10 h, 13 h and 16 h after flurazepam hydrochloride. Enhanced performance was observed at 34 h after nitrazepam and pentobarbitone sodium. 2 Increased reaction time persisted to 16 h after nitrazepam, flurazepam hydrochloride and pentobarbitone sodium and reaction time was also increased at 34 h after nitrazepam and pentobarbitone sodium. 3 During the morning immediately after ingestion, the subjects as a group were able to differentiate correctly between placebo and drugs, but they were not able to assess accurately the persistence of the residual effects of nitrazepam and pentobarbitone sodium. 4 Flurazepam hydrochloride would appear to be a more promising benzodiazepine than nitrazepam for use as a hypnotic by persons involved in skilled activity. There was a rapid recovery of performance during the afternoon and, unlike pentobarbitone sodium and nitrazepam, subjects retained the ability to recognize impaired skill.

Adult↗

PubMed1975

Behavioural sequelae of methaqualone in man and in the monkey (Macaca mulatta).

1 Residual effects in man of methaqualone hydrochloride (400 mg) were studied by adaptive tracking and by reaction time. Performance was measured at 10 h, 13 h, 16 h, 19 h and 34 h after the overnight ingestion of the drug. There was no evidence of impaired performance on adaptive tracking from 10 h to 19 h, but enhanced performance (P = 0.001) was observed 34 h after ingestion. With reaction time an increase (P = 0.01) was observed 10 h and a decrease (P = 0.05) was observed 19 h after ingestion. 2 Effects in the monkey (Macaca mulatta) of methaqualone (20 and 30 mg/kg body weight) were studied by a delayed matching task in which total response time was measured. No consistent effects on matching behaviour or on total response time were observed 2 h after intraperitoneal injection. 3 The studies suggest that methaqualone hydrochloride may be a valuable hypnotic for occasional use by persons involved in skilled activity.

Animals↗

PubMed1975

Immediate effects on human performance of a 1,5-genzodiazepine (clobazam) compared with the 1,4-benzodiazepines, chlordiazepoxide hydrochloride and diazepam.

1 The immediate effects on human performance of the 1,5-benzodiazepine, clobazam (20 mg), and the 1,4-benzodiazepines, chlordiazepoxide hydrochloride (20 mg) and diazepam (10 mg), were studied by adaptive tracking and measurement of reaction time. Each drug was ingested at 09.00 h and performance was measured at 09 h 30 min (0.5 h), 11 h 30 min (2.5 h), 14 h 30 min (5.5 h) and 18 h 30 min (9.5 h after ingestion). 2 With diazepam decrements in performance on adaptive tracking were observed at 0.5 h and 2.5 h and performance was enhanced at 9.5 h after ingestion. With clobazam performance at individual times did not differ significantly from control, but there was evidence of an improvement in performance during the day. There was no evidence of impaired performance on adaptive tracking after chlordiazepoxide hydrochloride. 3 Reaction time was slowed at 0.5 h and 2.5 h after diazepam and chlordiazepoxide hydrochloride. A decrease in reaction time was observed at 9.5 h after diazepam. No changes in reaction time were observed after clobazam. 4 The subjects as a group differentiated correctly between performance decrements on adaptive tracking after diazepam and the absence of performance decrements after clobazam and chlordiazepoxide hydrochloride. The persistence of the decrement in performance after diazepam was accurately assessed. 5 It is evident that the nature and persistence of impaired performance and the ability to appreciate impaired performance vary considerably between the benzodiazepines, and that the choice of a benzodiazepine should include careful consideration of performance sequelae.

Adult↗

PubMed1975

Considerations of vision and cerebral function during hypotension.

The currently held theory of preserved consciousness with impaired vision during positive acceleration is based on a maintained intraocular pressure and selective impairment of conduction in the peripheral visual pathway, though the experimental evidence does not wholly support this theory. During hypotension, intraocular pressure follows closely the arterial pressure, and conduction along the optic nerve is preserved as long as the electroretinogram persists. It is proposed that, though the mechanism of visual impairment during hypotension is related to events in the peripheral visual pathway, there are likely to be active forebrain events which preserve consciousness.

Acceleration↗

PubMed1975