Clapp W L, Madsen K M, Verlander J W, Tisher C C
Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville.
Lab Invest. 1989 Feb;60(2):219-30.
The qualitative and quantitative morphologic features of the cells lining the inner medullary collecting duct (IMCD) in the outer (IMCD1), middle (IMCD2) and inner (IMCD3) segments were investigated. Kidneys of male rats were fixed by in vivo vascular perfusion with glutaraldehyde and processed for light microscopy and scanning and transmission electron microscopy. The IMCD1 consisted of both principal cells and intercalated cells similar to those present in the outer medullary collecting duct. The principal cells were covered with small microvilli and a single cilium. Most of the IMCD2 and the entire IMCD3 contained one cell type (IMCD cell). When compared with the principal cells, the IMCD cells were taller, had fewer basal infoldings and a lighter staining cytoplasm containing numerous free ribosomes and small electron-dense cytoplasmic bodies in the basal region. The luminal surface was covered with prominent microvilli, but had no cilia. Morphometric analysis demonstrated that the surface density of apical and basal plasma membranes decreased from IMCD1 to IMCD3. However, because of an overall increase in tubule volume from IMCD1 to IMCD3, there were no significant differences in the absolute area of apical or basal membranes between the three segments. In contrast, the absolute area of lateral membranes increased significantly from IMCD1 to IMCD3. This study demonstrates that the IMCD1 consists of principal cells and intercalated cells similar to those in the outer medullary collecting duct, whereas the cells in most of the IMCD2 and the entire IMCD3 appear to represent a distinct and separate cell type which we choose to call the IMCD cell. Thus, both morphologic and functional heterogeneity appear to exist along the IMCD.
研究了外髓质集合管（IMCD1）、中髓质集合管（IMCD2）和内髓质集合管（IMCD3）段内衬细胞的定性和定量形态学特征。通过用戊二醛进行体内血管灌注固定雄性大鼠的肾脏，并进行光学显微镜、扫描电子显微镜和透射电子显微镜检查。IMCD1由主细胞和闰细胞组成，与外髓质集合管中的细胞相似。主细胞覆盖着小微绒毛和一根单纤毛。大多数IMCD2和整个IMCD3包含一种细胞类型（IMCD细胞）。与主细胞相比，IMCD细胞更高，基底褶更少，细胞质染色更浅，在基底区域含有大量游离核糖体和小的电子致密细胞质体。管腔表面覆盖着突出的微绒毛，但没有纤毛。形态计量分析表明，从IMCD1到IMCD3，顶端和基底质膜的表面密度降低。然而，由于从IMCD1到IMCD3小管体积总体增加，三段之间顶端或基底膜的绝对面积没有显著差异。相比之下，从IMCD1到IMCD3，侧膜的绝对面积显著增加。这项研究表明，IMCD1由与外髓质集合管中相似的主细胞和闰细胞组成，而大多数IMCD2和整个IMCD3中的细胞似乎代表一种独特的、独立的细胞类型，我们将其称为IMCD细胞。因此，沿IMCD似乎存在形态学和功能异质性。
