Acute effects of vasopressin V2-receptor antagonist on kidney AQP2 expression and subcellular distribution
Acute effects of vasopressin V2-receptor antagonist on kidney AQP2 expression and subcellular distribution
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DOI：
10.1152/ajprenal.1998.275.2.f285
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发表时间：
1998-08-01
影响因子：
4.2
通讯作者：
Nielsen, S
中科院分区：
文献类型：
--
作者：
Christensen, BM;Marples, D;Nielsen, S
研究了加压素V（2）受体拮抗剂OPC-31260（OPC）对大鼠肾脏水通道蛋白2（AQP 2）分布和表达的急性作用。免疫荧光和半定量免疫电子显微镜显示，15和30分钟的OPC治疗导致AQP 2的顶端质膜标记显着减少，同时增加标记的囊泡和多泡体。同时，OPC治疗诱导尿量大幅增加[0.6 +/- 0.2 vs. 8.3 +/- 1.0 ml/h（n = 4）]。北方印迹法显示，AQP 2 cDNA探针和地高辛标记的AQP 2 RNA探针在1.6 kb左右出现一条与预测的AQP 2 mRNA大小相一致的条带。在对照实验中，口渴增加，而水负荷降低AQP 2 mRNA水平。与静脉注射生理盐水的对照组相比，OPC治疗大鼠在治疗30 min内（52 +/-21%，n = 8，P < 0.025）和60 min内（56 +/-7%，n = 4，P < 0.001）导致AQP 2 mRNA显著降低。因此，在加压素受体拮抗剂治疗后观察到AQP 2 mRNA非常迅速的减少。在OPC处理24小时后，AQP 2 mRNA的减少持续（40 +/-17%，n = 5，P < 0.05）。利尿作用平行增加，尿渗透压降低。总之，阻断V（2）受体可使AQP 2迅速内化，同时使尿量迅速增加。此外，OPC治疗引起AQP 2 mRNA表达的快速和显着的减少，表明AQP 2表达的快速调节，AQP 2 mRNA水平的调节是通过加压素受体信号通路调节。
The acute effect of treatment with the vasopressin V(2)-receptor antagonist OPC-31260 (OPC) on aquaporin-2 (AQP2) distribution and expression in rat kidney was examined. Immunofluorescence and semi-quantitative immunoelectron microscopy revealed that 15 and 30 min of OPC treatment resulted in significant reduction in apical plasma membrane labeling of AQP2, with a concomitant increase in labeling of vesicles and multivesicular bodies. In parallel, OPC treatment induced a large increase in urine output [0.6 +/- 0.2 vs. 8.3 +/- 1.0 ml/h (n = 4)]. Northern blotting using a (32)P-labeled AQP2 cDNA probe and a digoxigenin-labeled AQP2 RNA probe revealed a band of similar to 1.6 kb corresponding to the predicted size of AQP2 mRNA. In control experiments, thirsting increased, whereas water loading decreased AQP2 mRNA levels. Treatment of rats with OPC caused a significant reduction in AQP2 mRNA within 30 min (52 +/- 21%, n = 8, P < 0.025) and 60 min (56 +/- 7%, n = 4, P < 0.001) of treatment compared with intravenous saline-injected controls. Thus a very rapid reduction in AQP2 mRNA was observed in response to vasopressin-receptor antagonist treatment. The reduction in AQP2 mRNA persisted after 24 h (40 +/- 17%, n = 5, P < 0.05) of OPC treatment. There was a parallel increase in diuresis and reduction in urine osmolality. In conclusion, V(2)-receptor blockade produced a rapid internalization of AQP2 parallel with a rapid increase in urine output. Furthermore, OPC treatment caused a rapid and significant reduction in AQP2 mRNA expression, demonstrating that for rapid regulation of AQP2 expression, modulation of AQP2 mRNA levels is regulated via vasopressin-receptor signaling pathways.