Four alkaloid derivatives of ibogamine were injected into the abdomens of cats with permanent brain electrodes. Tabernanthine tartrate and SAD 103 increased wakefulness, reduced slow wave sleep, and temporarily blocked paradoxical (REM) sleep. SAD 103's effects lasted much longer. The other two compounds, SAD 121 and SAD 122, had the opposite effect, slightly increasing both slow wave and paradoxical sleep. The findings suggest different ibogamine derivatives can either promote or suppress sleep stages, with implications for understanding the neurobiology of sleep.
Inhaling nitrous oxide produces a mix of depressive and activating effects on the central nervous system. In 9 volunteers, 25% and 50% nitrous oxide caused muscle relaxation, psychomotor slowing, and a shift in EEG toward slower waves with less alpha and more theta and delta activity, along with reduced amplitude of auditory evoked potential components. At the same time, it heightened sensory perceptions, caused perceptual illusions, and maintained high and prolonged contingent negative variation amplitude, suggesting CNS activation. This dual effect indicates a dissociative action at different levels of the central nervous system.