Antidepressant-Like Effects of Lycii Radicis Cortex and Betaine in the Forced Swimming Test in Rats

The purpose of the present study was to examine the effect of Lycii Radicis Cortex (LRC) and betaine (BT) on immobility and neurochemical change in the forced swimming test (FST) in the rat. LRC, BT or fluoxentine was administered intraperitoneally to Sprague-Dawley rats three times (1, 5 and 23.5 h) before the FST. To investigate antidepressant-like effect, serotonin (5-HT) and norepinephrine (NE) were examined in the hippocampus and hypothalamus of rats. LRC (100 mg/kg) and BT (30, 100 mg/kg) significantly decreased the immobility time in the FST. LRC (100 mg/kg) significantly increased both 5-HT and NE levels in the hypothalamus of rats exposed to FST. BT (100 mg/kg) significantly increased 5-HT levels in the hypothalamus and hippocampus of rats. Taken together, these results demonstrated that improvement in the behavioral changes after LRC and BT administration may be mediated by elevation of 5-HT level in the hypothalamus and hippocampus, indicating a possible antidepressant-like activity. The present results suggest that the efficacy of LRC and BT in an animal model of depression may provide anti-depressant effects in human, which remains to be determined.