Anti-anxiety effect of a novel 5-HT₃ receptor antagonist N-(benzo[d]thiazol-2-yl)-3-ethoxyquinoxalin-2-carboxamide (6k) using battery tests for anxiety in mice.

Objective: To investigate the anti-anxiety activity of "6k", a novel 5-hydroxytryptamine type 3 (5-HT₃) receptor antagonist in in mice.

Materials And Methods: Anti-anxiety activity of "6k" (1, 2, and 4 mg/kg, intraperitoneally (i.p.)) was evaluated in mice by behavioral tests such as elevated plus maze (EPM), open field test (OFT), light-dark box (L&D), and hole board test (HBT). Diazepam (2 mg/kg, i.p.) served as reference standard.

Results: "6k" significantly (P < 0.05) increased the time and entries in open arm in EPM as compared to vehicle control group. Further, "6k" significantly (P < 0.05) increased the central and peripheral ambulation along with rearings and time in central area; whereas, reduced the fecal pellets in OFT as compared to vehicle control group. There was significant (P < 0.05) reduction in the latency to enter dark chamber; whereas, increased number of crossings and time in light chamber in L&D aversion test by treatment with "6k" as compared to vehicle control group. In HBT, "6k" significantly (P < 0.05) increased the number of head dipping and squares crossed; whereas, reduced the latency for first head dip and number of fecal pellets as compared to vehicle control group.

Conclusion: A novel 5-HT3 receptor antagonist has anti-anxiety action.