[Facilitation of a state of wakefulness by semi-chronic treatment with sulbutiamin (Arcalion) in Macaca mulatta].

Cortical electroencephalographic (EEG) activities and nycthemeral states of vigilance organization were studied in 6 adult rhesus monkeys during subchronic administration (10 days) of Sulbutiamin, a synthesized derivative of thiamine (300 mg/kg/day). Sulbutiamin induced the following modifications: (1) In the EEG activities: increase in occurrence of fast rhythms (over 28 c/sec) during waking and also during slow sleep (SS) in which their amplitude doubled. SS spindles increased in number and amplitude. (2) In vigilance organization: waking was enhanced all along the 24 h recording and SS was reorganized (particularly at night), mostly light sleep: large decrease in stage 2 duration, increase in stage 1. REM sleep duration remained stable. These changes, occurring at around day 5 of the treatment, were more pronounced on day 10 and disappeared 2-5 days after withdrawal. This study demonstrated the clear action of Sulbutiamin upon the mechanisms regulating waking and light sleep.