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目的:通过检测多巴胺受体在正常大鼠下丘脑弓状核内神经肽Y(neuropeptide Y)和前阿黑皮素(proopiomelanocortin,POMC)神经元的表达和定位,以及在链脲佐菌素(streptozocin,STZ)诱导的糖尿病大鼠下丘脑表达的改变,探讨中枢多巴胺及其受体对血糖和机体能量代谢的影响。方法:大鼠分为糖尿病模型组(n=5)和实验对照组(n=8)。通过运用免疫荧光双标技术,在激光共聚焦显微镜下观察正常大鼠下丘脑弓状核内多巴胺受体的表达情况,以及这些受体与弓状核内参与能量代谢调节的一级神经元NPY神经元和POMC神经元的共定位关系;并应用Western Blot技术检测糖尿病状态下这些受体在弓状核内的表达量的改变。结果:正常大鼠弓状核内有D2DR和D5DR的表达,但没有D1DR、D3DR和D4DR的表达。几乎所有的NPY和POMC能神经元都表达D2DR和D5DR受体。在糖尿病状态下,大鼠弓状核内D2DR的表达显著减少(P<0.01),而D5DR则显著增多(P<0.05)。结论:正常大鼠弓状核神经元内表达D2DR和D5DR,糖尿病状态下其表达量发生变化。这些结果提示多巴胺可能通过弓状核内NPY和POMC能神经元上的多巴胺受体参与糖尿病的发生发展过程。
AIM: To detect the expression and localization of dopamine receptors in neuropeptide Y and proopiomelanocortin (POMC) neurons in the hypothalamic arcuate nucleus of normal rats, streptozocin (STZ) on the hypothalamus of diabetic rats and explore the effects of central dopamine and its receptors on blood glucose and body energy metabolism. Methods: The rats were divided into diabetic model group (n = 5) and experimental control group (n = 8). The expression of dopamine receptors in the hypothalamic arcuate nucleus of normal rats was observed under confocal laser scanning microscope by using double-labeling immunofluorescence technique. The levels of dopamine receptors in nucleus arcuatus and the primary neurons involved in energy metabolism in arcuate nucleus NPY Co-localization of neurons and POMC neurons. Western Blot was used to detect the changes of the expression of these receptors in the arcuate nucleus under the condition of diabetes mellitus. Results: There were D2DR and D5DR expression in normal rat arcuate nucleus but no expression of D1DR, D3DR and D4DR. Almost all NPY and POMC neurons express D2DR and D5DR receptors. D2DM expression was significantly decreased in the arcuate nucleus of diabetic rats (P <0.01), while D5DR was significantly increased (P <0.05). Conclusion: D2DR and D5DR are expressed in the nuclei of arcuate nucleus in normal rats. The expression of D2DR and D5DR changes in diabetic rats. These results suggest that dopamine may participate in the development of diabetes through the dopamine receptors on neurons of NPY and POMC in the arcuate nucleus.