促肾上腺皮质激素释放激素对原代培养海马神经元谷氨酸诱发电流的调节作用

Regulatory effect of corticotrophin-releasing hormone on glutamate-mediated current in cultured hippocampal neurons

目的:研究促肾上腺皮质激素释放激素(CRH)对原代培养海马神经元谷氨酸诱发电流(IGLU)的调节作用,并初步探讨其可能机制。方法:应用免疫荧光细胞化学方法观察原代培养的大鼠海马神经元CRH两型受体的表达;通过全细胞膜片钳技术研究CRH对海马神经元IGLU的调节作用及其可能涉及的胞内信号通路。结果:CRH作用2min明显抑制海马神经元IGLU,且呈剂量依赖性;细胞外给予CRH受体广谱拮抗剂α-helical CRH或CRHR1特异性拮抗剂antalarmin能完全阻断CRH对IGLU的抑制作用,CRHR2特异性拮抗剂astressin-2B对此没有明显作用;细胞内给予蛋白激酶C(protein kinaseC,PKC)的抑制剂G6976可阻断CRH对IGLU的抑制作用。结论:多肽类激素CRH可抑制原代培养的海马神经元IGLU,这种作用由CRHR1介导,并可能涉及PKC信号通路。

Objective：To examine the regulatory effect of corticotrophin-releasing hormone （CRH） on glutamate-mediated current （LGLU） in cultured hippocampal neurons and to study the related mechanism. Methods： Immunofluorescence analysis was used to investigate whether the cultured hippocampal neurons express CRH receptors, and the whole-cell patch-clamp technique was used to examine the direct modulation of CRH on LGLU and the possible intracellular signal pathway. Results： Two minutes＇ exposure to CRH obviously depressed LGLU in the neurons in a dose-dependent manner. CRH receptor antagonist a-helical CRH or CRH receptor type 1 （CRHR1） antagonist antalarmin completely blocked CRH-induced depression of LGLU ; whereas, CRH receptor type 2 （CRHR2） antagonist astressin-2B failed to block the effects of CRH. Application of the PKC inhibitor Go6976 totally blocked the CRH-induced decrease of LGLU. Conclusion： CRH can inhibit IGLU in primary cultured hippocampal neurons, which is mediated by CRHR1 and may involve the PKC signal pathway.