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(LGLU)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LGLU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a—helicalCRH或CRHRl特异性拈抗剂antalarmin能完全阻断CRH对LGLU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(proteinkinaseC,PKC)的抑制剂G06976可阻断CRH对LGLU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LGLU,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.