Rats given cannabidiol sleep more and experience other changes in their sleep-wake cycle, according to research published online in the Journal of Psychopharmacology on January 23.
Cannabidiol (CBD) is a major constituent of marijuana, but unlike the more well-known chemical delta-9-tetrahydrocannabinol (THC), it does not produce any psychoactive effects. The drug appears to have stimulatory effects at low doses and sedating effects at high doses.
“The knowledge concerning the effects of CBD in the neurobiology of the sleep-wake cycle contributes to elucidating the role of the endocannabinoid system not only in sleep phases, but also with respect to the full spectrum of action of CBD,” Marcos Hortes N Chagas of the University of São Paulo in Brazil and his colleagues explained.
For their study, the researchers administered various levels of CBD to adult rats and recorded their sleep-wake cycle. Electrodes implanted in the rats were used to record their brain-waves.
Rats slept more after being given CBD compared to rats given a placebo. Rats given the highest dose of CBD also took longer to enter into REM sleep, a stage of the sleep cycle associated with greater brain activity. There appeared to be no difference between the sleep-wake cycles on the following day, except that rats given a smaller dose of CBD entered into REM sleep quicker.