CRH对培养下丘脑神经元胞浆cAMP作用的探讨

Regulation of cAMP in rat hypothalamic neurons by exogeneous corticotropin-releasing hormone (CRH)

目的:研究促肾上腺皮质激素释放激素(CRH)对下丘脑神经元细胞内cAMP浓度的调节作用。方法:取孕17天胎鼠下丘脑分散培养下丘脑神经元,采用PTI(Photon Technology International,PTI)测量和分析外源性CRH对培养下丘脑神经元胞浆内游离钙浓度([Ca^(2+)]i)变化的影响,放射免疫方法测定神经元内cAMP含量,治疗组用CRHl受体特异性拮抗剂CP-154526处理下丘脑神经元后。结果:正常对照组的下丘脑神经元[[Ca^(2+)]i和cAMP含量较低,外源性CRH刺激后,[Ca^(2+)]i立即升高,神经元细胞内cAMP生成明显增加,预先应用CP—154526处理再用CRH刺激下丘脑神经元,各刺激组与对照组相比,差异显著。CP—154526可明显抑制CRH(10^(-6)mol/L)刺激的下丘脑神经元细胞内[Ca^(2+)]i和cAMP的生成增加。结论:CRH可通过与其1受体结合直接作用于下丘脑神经元,使神经元[Ca^(2+)]i和cAMP含量明显增加,在调节下丘脑神经元激活过程中CRH可能起了一定的重要作用。

Objective: To study the function and regulation of calcium signaling and in rat gypothalamic neurons by exogeneous cotricotropin-releasing hormone (CRH). Methods :Perifused primary cultures of rat hypothalamic neurons. Intracelluar free Ca2+ concentration ([Ca2+ ])i and cAMP were assayed at 32℃ by fluorescence analysis, the coverslip was mounted in a Delta Scan spectrofluorimeter(Photon Technology International), and by radioimmunoassay. Results: The basal lower intracellular cAMP and Ca2+ levels of perifused primary cultures of rat hypothalamic neurons cultured on coverslipy were markedly increased by CRH, and significantly attenuated by appliction of CP-154526. Conclusion: CRH may excite hypothalamic neurons directly suggest that cAMP and Ca2+ , suggesting a role of CRH type 1 receptor in the activation of CRH gene expression.