Effects of Valerian on the level of 5-hydroxytryptamine, cell proliferation and neurons in cerebral hippocampus of rats with depression induced by chronic mild stress

Abstract

To explore the effects of Valerian on the level of 5-hydroxytryptamine (5-HT), cell proliferation and neuron number in cerebral hippocampus of rats with depression induced by chronic mild stress. Seventy rats were divided into 7 groups: normal control, untreated, negative control, positive control, and low-, medium- and high-dose Valerian-treated groups. There were 10 rats in each group. Except for the normal control group, depression was induced in rats by chronic mild stress. The depressive rats in the other six groups were intragastrically administered with sodium carboxymethycellulose, fluoxetine, and low, medium and high-dose Valerian, respectively for 3 weeks. After the treatment, the proliferating cells in the hippocampus were labeled by injecting bromodeoxyuridine (BrdU) in 7 groups. The content of 5-hydroxytryptamine (5-HT) in the hippocampus was detected by high-performance liquid chromatography (HPLC), and the number of hippocampal neurons was counted by morphometry. Compared with the normal control group, the levels of 5-HT in the hippocampus in the low- and medium-dose Valerian-treated groups were increased and recovered to normal level. After the administration of low-dose Valerian for 3 weeks, the number of BrdU positive cells and neurons in the hippocampus of the depressive rats were recovered to the normal status. Minidose Valerian may promote the level of 5-HT and cell proliferation in the hippocampus of the depressive rats, and may play a role in saving injured neurons of the hippocampus.