Riluzole suppresses post-sigh, but not spontaneous apnoeas during sleep in rats

We conducted this experiment to determine the role of glutamate in the mechanism of sleep apnoeas by administering riluzole, a glutamate release inhibitor, to freely moving rats in which sleep-related apnoeas are physiological phenomena. Adult Sprague-Dawley rats were implanted with electrodes for electroencephalogram (EEG) and electromyogram (EMG) recording to monitor sleep and were placed inside a single-chamber plethysmograph to monitor respiration. Sleep and respiration were recorded for 6 h following intraperitoneal administration of 0.5, 5.0 and 10.0 mg kg(-1) riluzole. Riluzole dose-dependently suppressed post-sigh apnoeas during rapid eye movement (REM) sleep but had no effect on sleep-related spontaneous apnoeas. The drug (5.0 and 10.0 mg kg(-1)) also dose-dependently reduced wakefulness and increased sleep. It appears that glutamate, an excitatory neurotransmitter, plays a role in the genesis of the post-sigh apnoeas during REM sleep.