Effects of brotizolam on the sleep-waking cycle of the cat.

The effects of brotizolam (2-bromo-4-(2-chlorophenyl)-9-methyl-6H-thieno[3,2-f]-1,2,4-triazolo [4,3-a]-1,4-diazepine, We 941, Lendormin) on the sleep-waking behavior of freely moving cats was investigated by electroencephalographic and behavioral methods. In the cat brotizolam and triazolam increased the time asleep. With diazepam, sleep enhancement could be observed only within a very limited period. After nitrazepam and flurazepam sleep was decreased. REM-sleep was not changed with 0.1 mg/kg brotizolam, slightly reduced after 0.3 and moderately shortened with 1 mg/kg. After triazolam REM-sleep was reduced to a higher degree than after brotizolam. The experiments show, that brotizolam has sleep-inducing properties in the cat and is in this respect different from other diazepine derivatives.