Fine structure of the urinary bladder of the bullfrog, (Rana catesbiana)

Authors

  • Judy M. Strum,

    1. Cardiovascular Research Institute and the Departments of Medicine, and of Biochemistry and Biophysics of the University of California School of Medicine, San Francisco 94143
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  • David Danon

    1. Cardiovascular Research Institute and the Departments of Medicine, and of Biochemistry and Biophysics of the University of California School of Medicine, San Francisco 94143
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    • Patrick E. Gorman Professor of Biological Ultrastructure at the Weizmann Institute of Science, Rehovot, Israel, during the tenure of an American Heart Association Visiting Scientist Award on sabbatical leave of absence.


  • With the financial aid of U.S.P.H.S., National Heart and Lung Institute, grant HL 06285 and NIAMD grant AM 13659.

Abstract

The urinary bladder of the bullfrog, Rana catesbiana has been studied by light and electron microscopy. Three epithelial cell types were found: (1) granular cells, (2) mitochondria-rich cells, and (3) basal cells. The structure of the Rana catesbiana bladder differs from that of the toad Bufo marinus, in several respects: it lacks a mucous (goblet) cell type, its granular cells do not contact the underlying basement membrane, it has specialized, smooth-muscle cell-basal epithelial cell contacts, not previously described in amphibian bladders, and its mucosa is richly innervated. Mitochondria-rich cells within the bullfrog bladder epithelium were occasionally observed touching the basement membrane. The specialized smooth muscle-basal cell contacts provide anatomical evidence for how regulatory vasoactive substances such as neurohypophyseal peptides might alter epithelial geometry. Many nerve endings invest the mucosa just beneath the epithelial basement membrane in proximity to mitochondriarich cells and basal cells. The possible role of neural regulation in epithelial transport was discussed.

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