Three-dimensional structure of dense bodies in rabbit renal artery smooth muscle
✍ Scribed by McGuffee, Linda J. ;Mercure, Juanita ;Little, Sally A.
- Publisher
- John Wiley and Sons
- Year
- 1991
- Tongue
- English
- Weight
- 838 KB
- Volume
- 229
- Category
- Article
- ISSN
- 0003-276X
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✦ Synopsis
In this report, we present a three-dimensional computer assisted reconstruction study from serial thin sections through a rabbit renal artery smooth muscle cell. In a series of 32 consecutive thin (100-nm) sections, one longitudinally oriented cell was followed and photographed in alternating sections. The profiles of the cell surface and dense bodies were reconstructed from these 16 planes and the distribution, size, shape, and spatial relationships among these components was examined. The reconstructed images showed that the cell decreases in diameter from its widest region in the center to the two ends in a step-wise taper. Within the cell, dense bodies are numerous. Relative to the cell axes, a membrane associated dense body (MDB) can be 53.5 pm long, 0.25 pm wide, and may extend up to 2 pm in depth. While the MDB profile in one section may be aligned with the long axis of the cell, in an adjacent section the same dense body may appear almost circular or wedge shaped. The same is true of cytoplasmic dense bodies (CDBs). Compared with MDBs, CDBs are smaller in all dimensions. Some, but not all, CDBs line up in strings oriented with the long axis of the cell. The continuity of dense bodies over considerable cell depth and their change in shape may have important. implications for integration of contractile activity and for transmitting passive tension to the extracellular matrix.