Coordinated activity of sleep and arousal neurons for stabilizing sleep/wake states in Drosophila

SummaryThe output arm of the sleep homeostat in Drosophila is a group of neurons with projections to the dorsal fan-shaped body (dFSB) of the central complex in the brain. However, neurons that regulate the sleep homeostat remain poorly understood. Using neurogenetic approaches combined with ex vivo Ca2+ imaging, we identify two groups of sleep-regulatory neurons that modulate the activity of the sleep homeostat in an opposing fashion. The sleep-promoting neurons activate the sleep homeostat with glutamate, whereas the arousal-promoting neurons down-regulate the sleep homeostat’s output with dopamine. Co-activating these two inputs leads to frequent shifts between sleep and wake states. We also show that dFSB sleep homeostat neurons release the neurotransmitter GABA that inhibits octopaminergic arousal neurons. Taken together, we suggest coordinated neuronal activity of sleep- and arousal-promoting neurons is essential for stabilizing sleep/wake states.HighlightsGlutamate released by AstA neurons activates dFSBAstAR1 sleep-promoting neuronsDopamine down-regulates the activity of dFSBAstAR1 neuronsSimultaneous glutamate and dopamine input causes rapid sleep and awake swingsGABA released by dFSBAstAR1 neurons promotes sleep by inhibiting arousal neurons

Hypnotic Efficacy of Triazolam and Methyprylon in Insomniac In-Patients

The hypnotic effect of a new triazolobenzodiazepine, triazolam ( Halcion®) 0.5 mg and methyprylon 300 mg was compared in twenty oncologic inpatient volunteers with insomnia using the preference technique. On the first night of the two-night trial, triazolam or methyprylon was given on a double-blind basis and on the second night the patients received the alternate medication. Following each trial night the patients were interviewed in regard to their sleep. Of the seventeen patients who completed the study, eleven patients preferred triazolam, three preferred methyprylon and three had no preference ( p = 0.057). Analysis of the various sleep parameters showed that triazolam helped the patients sleep more than methyprylon ( p = 0.013), induced more rapid sleep onset ( p = 0.003), gave a longer duration of sleep ( p = 0.013). The treatment was considered a success if the patient went to sleep in thirty minutes or less and slept for at least six hours. Triazolam was more successful than methyprylon in this respect ( p = 0.012). There were no side-effects reported on either of the drugs.