The anxiolitic effects of BTG1640 and BTG1675A on ultrasonic isolation calls and locomotor activity of rat pups.

OBJECTIVE The aim of the present study was to evaluate the anxiolytic properties of the new isoxazoline compounds BTG1640 and BTG1675A in comparison with diazepam. MATERIALS AND METHODS We evaluated the ultrasonic distress emission in both sexes of neonatal rat pups (which seems to be a sensitive indicator of the rat emotional reactivity and represents a valuable tool to screen compounds with expected anxiolytic properties) and the locomotor activity in 30-day old rat pups. RESULTS We found a significant reduction in the number of emitted ultrasonic calls only after i.p. administration of diazepam 1 mg/kg, while no significant reduction have been detected after i.p. administration of BTG 1640 and BTG 1675A. Furthermore, we found a significant reduction of locomotor activity in the first 10' of the test, only in the group treated with diazepam 0.1 mg. CONCLUSIONS The tests validating the supposed anxiolytic properties of the new isoxazoline compounds BTG1640 and BTG1675A, in comparison with diazepam, gave negative results.