Effect of Intravenous Delivery of N,N Dimethyltryptamine on Sleep-Wake States in Rat

Abstract

Psychedelics, including N, N, Dimethyltryptamine (DMT), are being increasingly explored for therapeutic potential to treat psychiatric disorders such as depression, anxiety, and post-traumatic stress disorder. These and other psychiatric conditions have a bidirectional relationship with sleep patterns but the impact of psychedelics, particularly DMT, on sleep architecture is incompletely understood. Therefore, in this study, we determined the effect of intravenous DMT administration on sleep-wake states in male and female rats. Under surgical isoflurane anesthesia, adult Sprague Dawley rats (n=10, 5 male, 5 female) were instrumented with electrodes to record electroencephalogram (EEG) from across the cortex and electromyogram (EMG) from dorsal nuchal muscles. In addition, a chronic catheter was positioned in jugular vein for the infusion of DMT or 0.9% saline (as vehicle control). Each rat received an intravenous bolus (100 uL/min over 5 min) of either one of two doses of DMT (low dose: 3.75 mg/kg, high dose: 7.5 mg/kg) or 0.9% saline. The DMT and saline infusions were performed 30-minutes after the start of the lights-ON period (8:00 am) after which EEG and EMG data were recorded for 24h across the light and dark cycle. EEG and EMG data were manually scored (SleepSign, Kissei Comtec) in 4-second intervals and classified as wakefulness, slow-wave sleep, or rapid eye movement sleep, then averaged in 3h bins across the 24h recording period. A linear mixed model was used to compare the changes in percent time spent in each state, mean duration per episode for each state, and mean number of episodes for each state, between vehicle control and DMT infusion sessions. There was a statistically significant increase in the time spent in wakefulness in the first 3h bin after DMT infusion (p<0.02 for low dose, p<0.03 for high dose). In the same 3h bin, a significant decrease in slow-wave sleep (p<0.02 for low and high dose DMT) was observed. DMT infusion produced a significant increase in the latency to the onset of rapid eye movement sleep (p<0.01), but no statistical effect was observed on the time spent in rapid eye movement sleep during the light period. Our results with DMT align with previous reports showing an increase in wakefulness after administration of serotonergic psychedelics. Further analysis of neurophysiologic data is needed to understand the neural dynamics associated with DMT-induced increases in wakefulness. Department of Anesthesiology, University of Michigan. RS was partly supported by Magnificent Michigan Summer Undergraduate Research fellowship, University of Michigan. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.