The dual orexin receptor antagonist almorexant blocks the sleep-disrupting and daytime stimulant effects of methamphetamine in rhesus monkeys

Methamphetamine-Induced Sleep Impairments and Subsequent Slow-Wave and Rapid Eye Movement Sleep Rebound in Male Rhesus Monkeys

“…Importantly, methamphetamine decreased time spent in N3 and REM sleep even at doses that did not significantly decrease total sleep time. Of note, the overall effects of methamphetamine reported in this study are consistent with those previously reported under similar conditions, but using actigraphy-based sleep, in our laboratory ( Berro et al, 2021a ). In both studies, only the dose of 0.3 mg/kg of methamphetamine significantly increased sleep latency and decreased sleep efficiency (which can be inferred from the present study by the equation: total sleep time/12 h*100).…”

“…In both studies, only the dose of 0.3 mg/kg of methamphetamine significantly increased sleep latency and decreased sleep efficiency (which can be inferred from the present study by the equation: total sleep time/12 h*100). Our actigraphy-based sleep study showed a ∼700 ± 412% increase in sleep latency and a ∼24 ± 4% decrease in sleep efficiency following 0.3 mg/kg methamphetamine administration compared to baseline ( Berro et al, 2021a ), and our current data show a 150 ± 83% increase in sleep latency and a 30 ± 7% decrease in sleep efficiency compared to baseline. Different subjects were used in the two studies, which could explain some of the variability between the two data sets.…”

“… Herrmann et al (2017) showed that morning administration of oral methamphetamine disrupted polysomnography-based sleep parameters in recreational stimulant users, increasing latency to fall asleep and decreasing sleep efficiency. Corroborating these findings, we have shown previously that morning administration of methamphetamine disrupts actigraphy-based sleep parameters in rhesus monkeys, increasing sleep latency and decreasing sleep efficiency both in naïve monkeys ( Berro et al, 2021a ) and in monkeys with a chronic history of methamphetamine intake ( Berro et al, 2016 , 2017a , b ). Importantly, Herrmann et al (2017) also showed that methamphetamine dose-dependently decreased time in sleep stage N2 and in rapid eye movement (REM) sleep, as well as the number of REM sleep episodes.…”

“…While it is well known from the human literature that aging can influence sleep duration, particularly REM sleep duration ( Roffwarg et al, 1966 ), at least up until 15 years of age we do not see significant changes in sleep architecture with rhesus monkeys (results from the present study), and up to 20 years old, no age-related changes in actigraphy-based sleep have been reported ( Berro et al, 2021b ). We have previously reported that one 25 year old monkey in our colony showed longer baseline sleep latency and shorter baseline sleep duration compared to other monkeys (subject 98-003, Berro et al, 2021a ). However, other monkeys in our colony, as young as 9 years old, also show shorter sleep duration ( Berro et al, 2021a , 2022 ), demonstrating that, like humans, the sleep patterns of non-human primates may vary greatly between individual subjects.…”

“…We have previously reported that one 25 year old monkey in our colony showed longer baseline sleep latency and shorter baseline sleep duration compared to other monkeys (subject 98-003, Berro et al, 2021a ). However, other monkeys in our colony, as young as 9 years old, also show shorter sleep duration ( Berro et al, 2021a , 2022 ), demonstrating that, like humans, the sleep patterns of non-human primates may vary greatly between individual subjects.…”