He Duofen, Ren Hongmei, Wang Hongyong, Jose Pedro A, Zeng Chunyu, Xia Tianyang, Yang Jian
Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, China.
Chongqing Institute of Cardiology & Chongqing Key Laboratory of Hypertension Research, Chongqing 400042, China.
Cardiol Discov. 2023 Mar;3(1):24-29. doi: 10.1097/CD9.0000000000000076. Epub 2022 Oct 14.
Dopamine, via its receptors, plays a vital role in the maintenance of blood pressure by modulating renal sodium transport. However, the role of the D dopamine receptor (D receptor) in renal proximal tubules (PRTs) is still unclear. This study aimed to verify the hypothesis that activation of D receptor directly inhibits the activity of the Na-K-ATPase (NKA) in RPT cells.
NKA activity, nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) levels were measured in RPT cells treated with the D receptor agonist PD168077 and/or the D receptor antagonist L745870, the NO synthase inhibitor NG-nitro-L-arginine-methyl ester (L-NAME) or the soluble guanylyl cyclase inhibitor 1H-[1,2,4] oxadiazolo-[4,3-a] quinoxalin-1-one (ODQ). Total D receptor expression and its expression in the plasma membrane were investigated by immunoblotting in RPT cells from Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHRs).
Activation of D receptors with PD168077, inhibited NKA activity in RPT cells from WKY rats in a concentration- and time-dependent manner. The inhibitory effect of PD168077 on NKA activity was prevented by the addition of the D receptor antagonist L745870, which by itself had no effect. The NO synthase inhibitor L-NAME and the soluble guanylyl cyclase inhibitor ODQ, which by themselves had no effect on NKA activity, eliminated the inhibitory effect of PD168077 on NKA activity. Activation of D receptors also increased NO levels in the culture medium and cGMP levels in RPT cells. However, the inhibitory effect of D receptors on NKA activity was absent in RPT cells from SHRs, which could be related to decreased plasma membrane expression of D receptors in SHR RPT cells.
Activation of D receptors directly inhibits NKA activity via the NO/cGMP signaling pathway in RPT cells from WKY rats but not SHRs. Aberrant regulation of NKA activity in RPT cells may be involved in the pathogenesis of hypertension.
多巴胺通过其受体，在调节肾钠转运以维持血压方面发挥着至关重要的作用。然而，D2多巴胺受体（D2受体）在肾近端小管（PRT）中的作用仍不清楚。本研究旨在验证以下假设：D2受体的激活直接抑制肾近端小管（RPT）细胞中钠钾ATP酶（NKA）的活性。
在用D2受体激动剂PD168077和/或D2受体拮抗剂L745870、一氧化氮合酶抑制剂NG-硝基-L-精氨酸甲酯（L-NAME）或可溶性鸟苷酸环化酶抑制剂1H-[1,2,4]恶二唑并-[4,3-a]喹喔啉-1-酮（ODQ）处理的RPT细胞中，测量NKA活性、一氧化氮（NO）和环磷酸鸟苷（cGMP）水平。通过免疫印迹法研究了来自Wistar-Kyoto（WKY）大鼠和自发性高血压大鼠（SHR）的RPT细胞中总D2受体表达及其在质膜中的表达。
用PD168077激活D2受体，以浓度和时间依赖性方式抑制WKY大鼠RPT细胞中的NKA活性。添加D2受体拮抗剂L745870可阻止PD168077对NKA活性的抑制作用，而L745870本身无作用。一氧化氮合酶抑制剂L-NAME和可溶性鸟苷酸环化酶抑制剂ODQ本身对NKA活性无影响，但消除了PD168077对NKA活性的抑制作用。D2受体的激活还增加了培养基中的NO水平和RPT细胞中的cGMP水平。然而，SHR的RPT细胞中不存在D2受体对NKA活性的抑制作用，这可能与SHR的RPT细胞质膜中D2受体表达降低有关。
D2受体的激活通过NO/cGMP信号通路直接抑制WKY大鼠而非SHR的RPT细胞中的NKA活性。RPT细胞中NKA活性的异常调节可能参与高血压的发病机制。
