Shizuo Torii

The REM sleep-inducing action of a naturally occurring organic bromine compound in the encéphale isolé cat

The acute effects on the sleep-wakefulness cycle of 2-octyl-γ-bromo-acetoacetate (γ-Br), an organic bromine compound which occurs naturally in the brain and cerebrospinal fluid (CSF) of mammals, were studied in the encéphale isolé cat preparation under artificial respiration without fixation.In unmedicated preparations, the percentage of the three states, wakefulness, NREM sleep and REM sleep during the 3 h recording period was 32.8±15.59, 62.9±16.81 and 4.3±3.81, respectively.Various doses of synthetic γ-Br (0.1, 1.0 and 5.0 mg/kg) were injected intravenously. No central depressant effect was seen after injection of γ-Br up to 5 mg/kg. The effect of γ-Br on the sleep-wakefulness cycle was to increase REM sleep and to slightly decrease wakefulness or NREM sleep. Increase in REM sleep was significant (p<0.05) and its effective dose was 0.1 mg/kg. REM sleep-increasing effect appeared 5 to 15 min after injection. This coincided closely with the time of appearance of γ-Br in the CSF after intravenous injection.The relationship between γ-Br and short chain fatty acids as well as the possible mechanism related to REM sleep induction by γ-Br are discussed.

Effect of methylmercury chloride on sleep-waking rhythms in rats

Effects of methylmercury chloride (MMC) on circadian sleep-waking rhythms were examined in rats which had been chronically implanted with EEG and EMG electrodes. Bihourly distributions of wakefulness (W), slow wave sleep (SWS) and paradoxical sleep (PS) and 12-h amounts of W, SWS and PS during light and dark periods were measured before and after MMC administration for 2 successive days at 3 dose levels. A total dose of 10 mg MMC/kg body wt was found to be the threshold for inducing reversible changes in the sleep-waking patterns. A total dose of 30 mg MMC/kg produced an increase in both dark-phase SWS and PS as well as a decrease in light-phase PS at the expense of an increase in light-phase W and a delayed phase of the circadian PS rhythm. The delayed phase of the PS rhythm tended to persist after the increased SWS during the dark period returned to normal. Brain mercury concentrations were measured in order to find the dose-response relationship and the time dependence of the MMC-induced sleep disorder. The sleep-waking disorder was found to appear at lower levels of brain Hg and shorter latency than behavioral disorders of movement and postural maintenance previously reported [5-8].

The effect of butoctamide hydrogen succinate on nocturnal sleep: all-night polygraphical studies.

Butoctamide hydrogen succinate (BAHS), related to an organic compound naturally occurring in the central nervous system (CNS), has been shown to increase REM sleep in chronically prepared cats. In the present study, we confirmed that BAHS increases REM sleep in healthy humans. The subjects were six males whose mean age was 21 years and the experiment covered eight consecutive nights. Identical capsules containing either a placebo (linolenic acid) or 600 mg BAHS were administered 1 h prior to recording, which was started at 11 p.m. There was little change in total sleep time, sleep efficiency index, sleep latency, REM sleep latency, or the number of REM sleep periods during the drug- as compared to the baseline periods. There were, however, significant increases in REM sleep and decreases in sleep stages 1 and 2. The nights sleep was divided into three equal portions and analysis of the percentage of sleep stages in each showed that REM sleep markedly increased in the middle third while stages 3 and 4 increased in the last third. A carryover effect of BAHS was recognized during the with-drawal period. The maximum percentage of BAHS-induced REM sleep was 34%. REM density during the drug periods tended to decrease. These results suggest that BAHS may be an efficacious hypnotic in that it increase REM sleep which is suppressed by other clinically used hypnotics.

ELECTRICAL ACTIVITY OF HIPPOCAMPUS IN UNRESTRAINED RABBITS

The electrical activity of the hippccampus has been studied in unrestrained rabbits with electrodes chronically implanted in the brain. Simultaneous observations on the electrographical and behavioral chenges in free‐moving animals revealed that definite behavioral xanifestatiom were correlated with four levels of electrical activity of the hippocampus: (1) The excited state. The animal is exploring and its hippocampal activity shows regular slow waves at a frequency of 8 cycles per second. (2) The relaxed state. The animal is eating or licking and its hippocampal activity consists of 7 to 5 cycles per second slow waves. (3) The drowsy state. The animal lies down and its hippocampal slow waves are interspersed by fast activity, (4) The asleep state. The animal lies in a lateral position and closes its eyes and its hippocampal activity displays fast activity intermixed with irregular slow waves around 2 to 3 cycles per second. On the other hand, the electrical activity of the neocortex differs from that of the hippocampus in showing no definite correlation with the bzhavioral patterns. The dissociation between hippocampal and neocortical electrical activity has been pointed out, and its mechanism has been discussed from a phylogenetical point of view.

EEG Topography of Affective Response to Odors

Researchers in the past few decades have successfully employed electroencephalograms (EEGs) in their investigations of cerebral lateralization of mental functions [1–3]. For example, when the brain waves of a subject engaged in a spatial-oriented task (e.g., manipulating blocks to reconstruct a pattern from memory) are monitored, a decrease in alpha waves in the right hemisphere is seen, indicating activation of the right side of the brain during that task. Similarly, the left hemisphere usually shows decreased alpha-wave activity during a task that is more verbally focused. Also, the left and right cerebral cortex contribute differentially to the regulation of emotion. For example, greater left-frontal activation has been associated with reports of more intense positive affect in response to positive film clips, whereas greater right-frontal activation has been associated with more intense reports of negative affect in response to negative film clips [4].