The antidepressant-like effects of paeoniflorin in mouse models

Abstract

Peony is often used in Chinese herbal medicine for the treatment of depression-like disorders. Our previous studies have demonstrated that the total glycosides of peony exert antidepressant-like effects in animal models. Paeoniflorin is the main active glycoside of peony. The aim of this study was to evaluate the antidepressant-like effects of paeoniflorin in mice, as well as its active mechanisms. The results revealed that intraperitoneally injected paeoniflorin significantly reduced the duration of immobility in forced swimming and tail suspension tests. The doses that affected the immobility response did not affect locomotor activity. Furthermore, paeoniflorin antagonized reserpine-induced ptosis, akinesia and hypothermia. Paeoniflorin also significantly increased the levels of serotonin (5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) in the hippocampus. These results suggest that the upregulation of serotonergic systems may be an important mechanism for the antidepressant-like effects of paeoniflorin in mice.

Keywords: antidepressant-like effect; forced swimming; locomotor activity; neurotransmitter; paeoniflorin; reserpine; tail suspension.

Figure 1

Effect of paeoniflorin on the duration of immobility in the tail suspension test. Values are expressed as the mean ± standard error of the mean (SEM) with 11 mice in each group. Data analysis was performed using Dunnett’s test. ^*P<0.05 and ^**P<0.01 vs. the vehicle control group.

Figure 2

Effects of paeoniflorin on the duration of immobility in the forced swimming test. Values are expressed as the mean ± standard error of the mean (SEM) with 10 mice in each group. Data analysis was performed using Dunnett’s test. ^*P<0.05 and ^**P<0.01 vs. the vehicle control group.

Figure 3

Effects of paeoniflorin on locomotor activity in mice. Values are expressed as the mean ± standard error of the mean (SEM) with 10 mice in each group. Data analysis was performed using Dunnett’s test. There were no significant differences when compared with the vehicle control group.

Figure 4

Effects of paeoniflorin on monoamine neurotransmitters and a major metabolite of 5-HT in the hippocampus. Values are the mean ± standard error of the mean (SEM) with 8 mice in each group. Data analysis was performed using Dunnett’s test. ^*P<0.05 and ^**P<0.01 vs. the vehicle control group. NA, noradrenaline; 5-HIAA, 5-hydroxyindoleacetic acid; DA, dopamine; 5-HT, 5-hydroxytryptamine.