Assessment of hypnotic effects in the rat: Influence of the sleep-awake cycle

✍ Scribed by Dr. Leonard T. Meltzer; Kevin A. Serpa

• Publisher: John Wiley and Sons
• Year: 1988
• Tongue: English
• Weight: 463 KB
• Volume: 14
• Category: Article
• ISSN: 0272-4391
• DOI: 10.1002/ddr.430140206

✦ Synopsis

The influence of the sleep-awake cycle of the rat on the apparent hypnotic effects of two benzodiazepine hypnotics, triazolam (short half-life) and flurazepam (long half-life), was assessed. Cortical electroencephalographic recordings from freely moving animals were used to determine whether the rats were awake or asleep. When tested during the dark phase of the light-dark cycle, when rats sleep approximately 50% of each hour, both agents increased sleep, with flurazepam having a longer duration of action than triazolam. In contrast, when tested during the light phase of the light-dark cycle, when rats sleep approximately 70-90% of each hour, the sleep-inducing effects of the two agents could not be distinguished. These data emphasize the importance of baseline levels of sleep in assessing hypnotic-drug effects.