Jong-Hoon Ryu

A novel method for olfactory bulbectomy using photochemically induced lesion.

We present the photochemically induced olfactory bulbectomy (P-bulbectomy) as a novel method to ablate the olfactory bulb thus inducing an animal model of depression. The photosensitizer Rose Bengal was injected through the tail vein and then the cool halogen light illuminated the skull region overlying of the olfactory bulb for 10u2009min. Two weeks after surgery, P-bulbectomy had completely removed olfactory bulb uniformly in all animals. P-bulbectomy induced typical depression-related behaviors such as hyperactivity in the open field test and an enhancement of immobility time and in the forced swimming test. Depression-related neurohistological phenomenon was also seen; reduction of choline-acetyltransferase-positive cell numbers in the medial septum and a decline in cell proliferation in the dentate gyrus of hippocampus. This study shows that P-bulbectomy may be a convenient and reproducible experimental method to produce an animal model of depression.

Anxiolytic-like effects of Portulaca oleraceae L. using the elevated plus-maze in mice

SUMMARY The purpose of this study was to characterize the putative anxiolytic-like effects of the 70%ethanol extract of Portulaca oleracea (EPO) using an elevated plus maze (EPM) in mice. The EPOwas orally administered at 50, 100, 200 or 400 mg/kg to ICR mice, 1 h before the behavioralevaluation in the EPM, respectively. Control mice were treated with an equal volume of 10%tween 80, and positive control mice with diazepam (1 mg/kg). Single treatments of the EPOsignificantly increased the percentage of time spent and arm entries into the open arms of theEPM versus controls (P < 0.05). Moreover, there were no changes in the locomotor activity andmyorelaxant effects in any group compared with the saline controls. In addition, the anxiolytic-like effects of the EPO were blocked by flumazenil (10 mg/kg, i.p), a GABA A antagonist not byWAY 100635 (0.3 mg/kg, i.p), a 5-HT 1A receptor antagonist. These results indicate that P. oleraceais an effective anxiolytic agent, and suggest that the anxiolytic-like effects of P. oleracea ismediated via the GABAergic nervous system.Key words: Anxiety; Portulaca oleracea; Elevated plus-maze; WAY 100635; Flumazenil