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目的观察多巴胺 D_3受体对肾脏近曲小管(RPT)上皮细胞上多巴胺 D_3受体表达和功能的影响。方法以 Wistar-Kyoto(WKY)大鼠与自发性高血压大鼠(SHR)为研究对象,利用免疫印迹法观察 D_3受体对 D_5受体蛋白表达的影响;并采用 Na~+-K~+-ATP 酶活性测定方法在转染 D_5受体的人胚肾293细胞(HEK293-D_5)上观察D_3受体对 D_5受体影响的病理生理学意义。结果刺激 D_3受体可增强 D_5受体的蛋白表达,该作用呈浓度和时间依赖性;同时能被 D_3受体特异性阻断剂所阻断;在高血压状态下,这种作用受损。刺激 D_5受体可抑制 Na~+-K~+-ATP 酶的活性,在预先刺激 D_3受体的情况下可使 D_5受体对 Na~+-K~+-ATP 酶活性的抑制作用进一步增强。结论D_3受体对肾脏近曲小管上皮细胞上 D_5受体的表达和功能具有促进作用,这种作用的受损可能在原发性高血压的发生发展中具有一定影响。
Objective To investigate the effect of dopamine D_3 receptor on the expression and function of dopamine D_3 receptor on renal proximal tubule (RPT) epithelial cells. Methods Wistar-Kyoto (WKY) rats and spontaneous hypertensive rats (SHR) were used as experimental objects. The effect of D 3 receptor on the expression of D 5 receptor protein was observed by immunoblotting. The Na ~ + -K + -ATPase activity assay The pathophysiological significance of D_3 receptor on D_5 receptor was observed on HEK293-D_5 cells transfected with D_5 receptor. Results Stimulation of D_3 receptor enhanced the expression of D_5 receptor protein in a concentration - and time - dependent manner. It was also blocked by D_3 receptor - specific blockers and impaired in hypertensive rats. Stimulation of D_5 receptor inhibited the activity of Na ~ + -K ~ + -ATPase, which could further enhance the inhibitory effect of D_5 receptor on Na ~ + -K ~ + -ATPase activity by stimulating D_3 receptor in advance. . Conclusion D_3 receptor may promote the expression and function of D_5 receptor on renal proximal tubule epithelial cells. The impairment of D_3 receptor may play an important role in the development and progression of essential hypertension.