ISSN:
1432-0878
Keywords:
Kidney
;
Rat
;
Actin- and myosin-like filaments
;
Tubule and interstitial cells
;
Electron microscopy
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary By electron microscopy, the prominent bundles of filaments occurring in the basal part of proximal and distal tubule cells and in interstitial cells of rat kidney cortex were studied in cells fixed by vascular perfusion, in glycerol-extracted cells and in glycerol-extracted cells treated with heavy meromyosin (HMM). The studies of perfusion-fixed tissue showed that the proximal tubule cells contained in their most basal part filamentous bundles oriented transversely around the tubule. The bundles consisted of trightly packed thin filaments (50–80 Å in diameter). Similar but less prominent bundles were found in distal tubule cells and in interstitial cells. The dimension of these filaments was similar to that of actin filaments and their insertion in the basal cell membrane of the tubule epithelial cells resembled the insertion of actin filaments in the cell membrane of smooth muscle cells. The studies on glycerol-extracted cells revealed that some tubule cells contained two types of filaments (60–80 Å and 130–170 Å in diameter) located side by side in the basal filamentous bundles. The dimension of the thick filaments corresponds well to the values for myosin filaments in glycerinated smooth and skeletal muscle. The studies on HMM-reacted renal tissue revealed that the thin filaments (60–80 Å) described in tubule and interstitial cells are probably actin filaments, as they formed characteristic arrowhead complexes morphologically indistinguishable from the complexes of HMM with actin filaments in smooth and striated muscle cells. Our results provide strong evidence that a two-filament contractile system, based on interaction of actin and myosin filaments, exists in renal tubule and interstitial cells. As a hypothesis it is proposed that it is changes in tonus of the basal filamentous system in the proximal tubule cells which stabilize the intratubular pressure, possibly via angiotensin.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00306638
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