Fischer E, Schnermann J, Briggs J P, Kriz W, Ronco P M, Bachmann S
Department of Anatomy and Cell Biology I, University of Heidelberg, Germany.
Am J Physiol. 1995 Jun;268(6 Pt 2):F1164-76. doi: 10.1152/ajprenal.1995.268.6.F1164.
The presence of NO synthase (NOS) in cells of the macula densa (MD) suggests a role for arginine-derived NO in tubulovascular information transfer. To investigate the postnatal development of the neuronal isoform of NOS and of renin in the kidney, the cellular distribution of these enzymes was examined in perfusion-fixed kidneys of 2-, 6-, and 15-day-old rats at both the protein and mRNA level (n = 4 rats/group). NOS and renin and their mRNAs were localized by immunohistochemical and in situ hybridization methods. In addition, NOS levels were assessed by using NADPH diaphorase (NADPH-d) histochemistry. For quantification, the fraction of NOS- and renin-positive glomeruli as well as the number of NOS-positive MD cells was evaluated at all stages. Presence of NOS in single cells of the developing distal tubule was encountered already in the S-shaped body. Full expression of a NOS signal in MD cells was seen as soon as a glomerular urinary space was developed. Double labeling with NADPH-d and antibody to Tamm-Horsfall protein (THP) indicated mutual exclusiveness of NADPH-d-positive MD cells and neighboring THP-positive distal tubule cells at all levels of development. The relative intensity of renin status was 2 day > 6 day > 15 day, whereas NOS expression was maximal on postnatal day 6. Our data are consistent with an involvement of MD NO synthesis in the early organization of the juxtaglomerular apparatus during nephrogenesis and suggest an interdependent relation with renin-producing cells.
致密斑（MD）细胞中存在一氧化氮合酶（NOS），这表明精氨酸衍生的一氧化氮在肾小管-血管信息传递中发挥作用。为了研究肾脏中NOS神经元亚型和肾素的出生后发育情况，在蛋白质和mRNA水平上检测了2日龄、6日龄和15日龄大鼠灌注固定肾脏中这些酶的细胞分布（每组n = 4只大鼠）。通过免疫组织化学和原位杂交方法对NOS、肾素及其mRNA进行定位。此外，使用NADPH黄递酶（NADPH-d）组织化学评估NOS水平。为了进行定量分析，在所有阶段评估了NOS和肾素阳性肾小球的比例以及NOS阳性MD细胞的数量。在S形小体中就已经在发育中的远端小管的单个细胞中发现了NOS。一旦肾小球尿腔形成，MD细胞中就会出现完整的NOS信号表达。用NADPH-d和抗Tamm-Horsfall蛋白（THP）抗体进行双重标记表明，在所有发育阶段，NADPH-d阳性MD细胞与相邻的THP阳性远端小管细胞相互排斥。肾素状态的相对强度为2日龄＞6日龄＞15日龄，而NOS表达在出生后第6天最高。我们的数据表明MD中NO合成参与了肾发生过程中肾小球旁器的早期组织形成，并提示与产生肾素的细胞存在相互依存关系。
