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.