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Histochemical carbonic anhydrase in rat inner medullary collecting ductRat inner medullary collecting duct (IMCD) secretes substantial amounts of H+. However, carbonic anhydrase (CA), a concomitant of H+ secretion, has been generally reported absent in this segment. To reexamine this problem, we investigated CA and the morphological phenotypes of cells comprising the IMCD by CA histochemistry, using a modified Hansson technique with light and electron microscopy. Throughout the medulla, tubule cells exhibit histochemical CA activity. In the initial third of the inner medulla, a small proportion have features of intercalated cells and demonstrate some degree of CA activity. However, the majority population in the early portions of the IMCD appears to consist of principal cells. These also show CA staining of widely variable intensity, both among and within cells. A third cell type, previously called "IMCD cells", appears in the middle portion of the IMCD and is the only cell type present near the papilla tip. In contrast to previous reports, these "IMCD cells" have histochemical CA staining, also of highly variable intensity. These results demonstrate that stainable carbonic anhydrase to support acidification is present throughout the rat IMCD, both in intercalated cells and in some cells clearly not of this type. Therefore, the presence of CA is not specific for the intercalated cell type and suggests that other cell types may participate in acid secretion in IMCD.
Document ID
20050000592
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Kleinman, J. G.
(Zablocki Veterans Affairs Medical Center Milwaukee, WI 53295)
Bain, J. L.
Fritsche, C.
Riley, D. A.
Date Acquired
August 22, 2013
Publication Date
October 1, 1992
Publication Information
Publication: The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society
Volume: 40
Issue: 10
ISSN: 0022-1554
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Musculoskeletal
Non-NASA Center

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