Effect of subchronic administration of fluoxetine (10 mg/kg, 32.3 µmol/kg), compound 14 (10 mg/kg, 37.4 µmol/kg) and compound 21 (1.0 mg/kg, 1.6 µmol/kg) on immobility in the forced-swim test in Balb/c mice. Vehicle or the test agent was injected i.p. 23, 5, and 1 hr prior to the test. n = 10–11; * P < 0.05 vs. vehicle.