Abstract. In the present study, the characteristics of the sleep features of amitriptyline, mexiletine, and N-(4-tertiarybutylphenyl)-4-(3-cholorphyridin-2-yl)tetrahydropyradine-1(2H)-carbox-amide (BCTC) were studied. Electrodes were chronically implanted into the frontal cortex and the dorsal neck muscles of rats for electroencephalogram (EEG) and electromyogram (EMG) measurements, respectively. EEG and EMG were recorded with an electroencephalograph, and SleepSign ver. 2.0. was used for sleep-wake state analysis. Recordings were performed from 11:00 to 17:00. Amitriptyline caused significant decreases in sleep latency and total wake time and an increase in total non-rapid eye movement (non-REM) sleep time. Mexiletine caused a significant decrease in sleep latency, but no significant effect was observed in total wake time and total non-REM sleep time. On the other hand, BCTC, which is an antagonist of transient receptor potential vaniloid 1 (TRPV1), showed no significant effect on sleep latency, total wake time, total non-REM sleep time, and total REM sleep time. From these results, it can be concluded that a TRPV1 antagonist may become a useful drug for neuropathic pain without sedative side effects in the daytime, different from amitriptyline and mexiletine.

The present study was performed to investigate the effects of histamine H 1 -antagonists on the sleep-awake state in rats placed on a grid suspended over water in comparison with rats placed on sawdust. When rats were placed on the grid suspended over water, significant increases in the awake time and decreases in non-rapid eye movement (non-REM) sleep time were observed compared with in rats on sawdust, even when measured hourly for 6 h. Diphenhydramine, chlorpheniramine and promethazine caused a significant decrease in the awake time and increase in non-REM sleep time in rats placed on the grid suspended over water for 1-2 h and/or 2-3 h after administration. On the other hand, in rats placed on sawdust, no significant differences were observed in the awake time and non-REM sleep time with diphenhydramine and chlorpheniramine compared with the control. Different from these two drugs, promethazine caused a significant decrease in the awake time and increase in non-REM sleep time 1-2 h and 2-3 h after administration even when rats were placed on sawdust at a relatively high dose. These results clearly indicate that histamine H 1 -antagonists had potent effects on decreasing the awake time and increasing non-REM sleep time under the conditions of an activated histaminergic system.

Abstract. The present study was performed to investigate the effects of kavain on the sleepwake cycle in comparison with that of rilmazafone and diphenhydramine using sleep-disturbed rats. Electrodes for the electroencephalogram (EEG) and electromyogram (EMG) were implanted into Wistar rats. Total awake time, non-rapid eye movement (non-REM) sleep and rapid eye movement (REM) sleep were measured for 6 h. Kavain and rilmazafone showed a significant shortening in sleep latency, decreased awake time, and increased non-REM sleep time. On the other hand, significant shortening of the sleep latency was observed following the administration of diphenhydramine, while no effects were observed on the awake and non-REM sleep time. Moreover, kavain showed a significant increase in delta activity during non-REM sleep in sleepdisturbed rats, whereas a significant decrease in delta power during non-REM sleep was observed with rilmazafone. These results clearly indicate that kavain is a compound with not only hypnotic effects, but also sleep quality-enhancement effects.

The aim of this study was to compare the effect of the serotonin (5-HT) 1A

The present study was undertaken to investigate the effect of ethanol on the sleep-wake cycle in normal rats and sleep-disturbed rats. In normal rats, no significant difference was observed by ethanol in sleep latency, total awake time and total non-rapid eye movement (NREM) sleep time, except for total REM sleep time. On the other hand, in sleep-disturbed rats, ethanol at doses of 1 and 2 g/kg caused significant decreases in sleep latency and total wake time, and an increase in total NREM sleep time. In addition, ethanol showed a significant increase in delta activity in the sleep-disturbed model rat, different from triazolam. These results suggested that ethanol had not only a hypnotic but also a sleep-maintaining effect in sleep-disturbed rats at reasonable blood ethanol concentrations.