Similar effects of diazepam and the 5-HT3 receptor antagonist ICS 205-930 on place aversion conditioning.

The anti-anxiety effect of diazepam and the antagonist of 5-HT3 receptors, ICS 205-930, was studied with a conditioned place aversion test design. The results showed that when one of two distinctive and previously preferred compartments was associated with an inescapable footshock, the control animals avoided that compartment in the post-conditioning test. Both diazepam (1-4 mg/kg i.p.) and ICS 205-930 (0.125-1.0 mg/kg i.p.), given before the post-conditioning test, increased in a dose-dependent manner the amount of time spent by the animals in the compartment conditioned to footshock. The results support the view that central 5-HT3 receptors may be involved in the control of anxiety.