ANTIANXIETY AND BEHAVIORAL SUPPRESSANT ACTIONS OF THE NOVEL 5-HT1A RECEPTOR AGONIST, FLESINOXAN

Flesinoxan is a potent and selective 5-HT1A receptor agonist. In this study, the effects of this compound on behavior in the murine elevated plus-maze have been assessed using a recently developed ethological scoring method. Results show that, at low doses (0.1-0.5 mg/kg), flesinoxan inhibited risk assessment behaviors (stretched attend postures and closed arm returns) indicative of a reduction in anxiety. These effects were maintained at a higher dose of 1.0 mg/kg, which also increased percent open entries and time spent on the central platform and open arms. However, this more convincing anxiolytic profile was associated with significant reductions in total arm entries and rearing, suggesting a combination of anxiolysis and behavioral suppression at high doses. The plus-maze profile observed with flesinoxan is very similar to that previously reported for 8-OH-DPAT in the same test but, despite superficial similarities, can be distinguished from that seen with buspirone. Data are discussed in relation to behavioral similarities and differences between 5-HT1A receptor agonists, and the advantages of a more detailed approach to the analysis of plus-maze behavior.