目的　为了进一步探讨抗抑郁药作用的分子机制。方法　采用原位杂交技术 (地高辛标记的BDNFcDNA探针 )检测长期给予抗抑郁药氟西汀及生理盐水大鼠海马神经元BDNFmRNA的表达。结果　与生理盐水组相比 ,氟西汀组表达增强 ,尤以CA3、CA1区为甚。结论　长期给药后脑内有关区域BDNF表达改变可能是抗抑郁效应发生的受体后分子作用机制之一 Objective To further explore the molecular mechanism of antidepressant effect. Methods The expression of BDNF mRNA in the hippocampal neurons of long-term anti-depressant fluoxetine and saline-treated rats was detected by in situ hybridization (digoxigenin labeled BDNF cDNA probe). Results Compared with saline group, fluoxetine group increased expression, especially in CA3 and CA1 regions. Conclusion The change of BDNF expression in the relevant brain regions after long-term administration may be one of the mechanisms of post-receptor molecular action of antidepressant effect