Jensen B L, Stubbe J, Hansen P B, Andreasen D, Skøtt O
Department of Physiology and Pharmacology, University of Southern Denmark-Odense, DK-5000 Odense C, Denmark.
Am J Physiol Renal Physiol. 2001 Jun;280(6):F1001-9. doi: 10.1152/ajprenal.2001.280.6.F1001.
We investigated the localization of cAMP-coupled prostaglandin E(2) EP2 and EP4 receptor expression in the rat kidney. EP2 mRNA was restricted to the outer and inner medulla in rat kidney, as determined by RNase protection assay. RT-PCR analysis of microdissected resistance vessels and nephron segments showed EP2 expression in descending thin limb of Henle's loop (DTL) and in vasa recta of the outer medulla. The EP4 receptor was expressed in distal convoluted tubule (DCT) and cortical collecting duct (CCD) in preglomerular vessels, and in outer medullary vasa recta. Butaprost, an EP2 receptor-selective agonist, dose dependently raised cAMP levels in microdissected DTL and outer medullary vasa recta specimens but had no effect in EP2-negative outer medullary collecting duct segments. Dietary salt intake did not alter EP2 expression in the kidney medulla. These results suggest that PGE(2) may act in the resistance vessels and in the DTL and DCT-CCD segments as a paracrine, cAMP-dependent regulator of vascular resistance and tubular transport, respectively.
我们研究了环磷酸腺苷（cAMP）偶联的前列腺素E2（PGE2）EP2和EP4受体在大鼠肾脏中的表达定位。通过核糖核酸酶保护试验确定，EP2信使核糖核酸（mRNA）局限于大鼠肾脏的外髓质和内髓质。对显微切割的阻力血管和肾单位节段进行逆转录聚合酶链反应（RT-PCR）分析显示，EP2在亨氏袢降支细段（DTL）和外髓质直小血管中表达。EP4受体在肾小球前血管的远曲小管（DCT）和皮质集合管（CCD）以及外髓质直小血管中表达。EP2受体选择性激动剂布他前列素剂量依赖性地提高了显微切割的DTL和外髓质直小血管标本中的cAMP水平，但对EP2阴性的外髓质集合管节段没有影响。饮食盐摄入量并未改变肾髓质中EP2的表达。这些结果表明，PGE2可能分别在阻力血管以及DTL和DCT-CCD节段中作为旁分泌、依赖cAMP的血管阻力和肾小管转运调节剂发挥作用。
