BACKGROUND: Severe or prolonged stress is harmful to health and even induces many mental and physical disorders and then impairs cognitire functions of the organism.OBJECTIVE: To investigate the effects of stress on the changes in amino acid and chronic stress on long-term potentiation (LTP) of hippocampus of rats.DESIGN: Completely randomized controlled experiment.SETTING: Mental Health Center of Shantou University.MATERIALS: The experiment was completed in the Medical College of Shantou University in December 2000. Totally 16 adult male SD rats were divided randomly into control group and stress group with 8 in each group.METHODS: Mice in stress group were swum compulsively for 4 weeds.Chronic stress model was established, and isolated hippocampal slice(500 μm) combined with electrophysiological technique was used to observe the changes of LTP in hippocampal CA1 field. High-frequency stimulation (HFS) was applied to Schaffer collaterals in hippocampus CA3, then the changes of PS amplitude and fEPSPs slope in CA1 pyramidal neurons were observed. High performance liquid chromatography (HPLC) coupled with UV detection was used for the quantificative analysis of hippocampal amino-acid neurotransmitters.MAIN OUTCOME MEASURES: ① Population spike (PS) amplitude and field excitatory postsynaptic potentials (fEPSPs) slope were used to indicate the changes of LTP. ② Changes of amino acid of hippocampus.RESULTS: One rat in stress group died because of drowning in the second week of experiment was supplied, and others entered the final analysis. ① The increases of PS amplitude and fEPSPs slope after HFS in control group were significantly higher than those in stress group (P＜ 0.05). ② The levels of aspartate and glutamate in control group were significantly lower than those in stress group [(2.425±0.211) μmol/g,(6.016±0.677) μmol/g. P＜ 0.01; (4.746±0.609) μmol/g. (8.094±1.035) μmol/g.P ＜ 0.01]; but there was no significant difference of γ-aminobutyric acid between control and stress groups [(4.229±0.449) μmol/g, (4.249± 0.463) μmol/g, P ＞ 0.05].CONCLUSION: It is suggested that chronic stress can inhibit the development of LTP in hippocampal CA1 field and increase the levels of hippocampal aspartate and glutamate, but does not affect the level of γ-aminobutyric acid. The accumulation of hippocampal excitatory amino acids induced by chronic stress may be the neurobiochemical basis of impairments in learning and memory abilities.

Objective To explore the effects of YOGA relaxation on anxiety and somatic symptoms in patients with depression. Methods 60 inpatients with depression were ctegorized into the control group and the observation group with 30 cases in each group. HAMD scale were scored before and after medication (2,4,8 weeks). Results Before medication, there was no statistical differenoe between two groups in HAMD total score and subscores, but the difference was obvious in anxiety and somatic, sleep disturbance and hopelessness subscore at the end of the second and 4th week. Conclusions YOGA relaxation can improve anxiety emotion and somatic symptoms, enhance sleep quality in patients with depression.