低频重复经颅磁刺激对抑郁模型大鼠游泳及海马内氨基酸递质的影响

目的 观察低频重复经颅磁刺激（rTMS）对慢性应激抑郁模型大鼠强迫游泳试验及海马内氨基酸递质含量的影响，探讨低频rTMS对抑郁症的治疗作用及其机制。方法 选用12只SD雄性大鼠制备慢性不可预见性温和应激抑郁模型，造模后随机分为磁刺激组和抑郁模型组，磁刺激组给予低频rTMS治疗，并与正常对照组比较。各组大鼠于磁刺激前、后进行强迫游泳试验，并采用高效液相色谱法检测大鼠海马内氨基酸递质的含量。结果 抑郁模型组大鼠模拟磁刺激后，强迫游泳试验中不动时间与模拟磁刺激前比较，差异无统计学意义（P〉0．05），而与正常对照组比较显著增高（P〈0．01）。磁刺激组大鼠磁刺激后，强迫游泳试验中不动时间与磁刺激前比较明显降低（P〈0．01）；与抑郁模型组模拟磁刺激后比较，也明显降低（P〈0．01）；与正常对照组比较，差异无统计学意义（P〉0．05）。抑郁模型组大鼠海马内谷氨酸含量明显低于正常对照组和磁刺激组（P〈0．05）；磁刺激组大鼠海马内谷氨酸含量与正常对照组比较，差异无统计学意义（P〉0．05）。结论 低频rTMS能明显改变慢性应激抑郁模型大鼠的抑郁行为；对海马内氨基酸递质水平的调节作用具低频rTMS的抗抑郁机制之一.

Effects of low frequency repetitive transcranial magnetic stimulation on forced swimming and amino acid neurotransmitters in the hippocampus in a rat model of chronic depressive stress

Objective To observe any changes in forced swimming and in the amino acid neurotransmitters in the hippocampus of rats subjected to chronically depressive stress after low frequency repetitive transcranial magnetic stimulation(rTMS) , and to study the therapeutic effects and the mechanism of low frequency rTMS in treating depression. Methods Twelve male Sprague-Dawley rats were exposed to an unpredictable sequence of mild stressors to establish a model of depression. The depressed rats were then randomly allocated into two groups: a depressed control group, and a magnetic stimulation group. Another 6 normal rats served as normal controls. Before and after the repetitive transcranial magnetic stimulation treatment, the rats were evaluated in terms of their behavior on a forced swimming test, and the concentrations of amino acid neurotransmitters in the hippocampuses of the rats in all three groups were measured. Results Rats in the depressed control group showed no significant difference in immobility time on the forced swimming test pre-and post-treatment, but their immobility time was significantly different from that of the control group (P<0.01). The rats in the magnetic stimulation group showed a significant reduction in immobility time compared with both their pre-treatment times and the times of the depressed control group (P <0.01 ). The times for the rats in the magnetic stimulation group were not significantly different from those of the normal controls. The level of glutamate in the hippocampus in the depressed controls was lower than that in the normal controls (P < 0. 05). The level of glutamate in the hippocampus in the magnetic stimulation group was higher than that in the depressed control group ( P < 0. 05 ) . There was no significant difference in glutamate levels between the magnetic stimulation group and the normal controls. Conclusion Low frequency rTMS can change the depressive behavior of rats with experimentally induced depression. Regulating the level of amino acid neurotransmitters in the hippocampus might be one of the antidepressive mechanisms of low frequency rTMS.