Shape changes produced in detergent extracted bovine retinal pigment epithelium when exposed to ATP. A comparison with fibroblasts and smooth muscle cells.

The response of single detergent treated bovine retinal pigment epithelial cells in culture to ATP was measured with an image analyser. The most pronounced contraction was produced by 1.0 mM ATP with most change taking place in the first 10 min. At 1 h the area had decreased by about 33%, perimeter 22% and maximum length 25%. By way of comparison rabbit skin fibroblasts had a decreased area of approximately 40%, perimeter 25% and maximum length 22%. Bovine aortic smooth muscle cells on the other hand decreased in area by 55%, perimeter 40% and maximum length 36%. It is hoped that this assay may be used to evaluate drugs which could counteract contractile events in proliferative vitreoretinopathy.

Investigations of cytoskeletal elements in cultured bovine meshwork cells.

An ultrastructural, immunohistochemical, and functional study was conducted on cultured bovine meshwork cells. Particular emphasis was placed on the organization of the cytoskeleton, and the cells were viewed either as whole cells or following detergent extraction. For ultrastructural examination, several modes of viewing were adopted, including a detector situated above the specimens collecting secondary electrons (SE), a detector situated beneath the specimen collecting transmitted electrons (STEM), and conventional transmission electron microscopy at 100 KV (TEM). In whole cell mounts, information was obtained about the organization of the cytoskeleton and its relationship to other cytoplasmic organelles. Extraction procedures removed much of the plasma membrane and most organelles. The nucleus and cytoskeleton remained and stress fibers were prominent. Immunohistochemistry showed that the actin content of the cytoskeleton could be preserved after detergent extraction. Detergent-extracted cells decreased their surface area when exposed to MgATP in a dose-dependent manner. The decrease in surface area was associated with disassembly of cytoskeletal stress fibers and was optimal with 1 mM MgATP. Whether or not the change in surface area could be considered a "contractile event" was discussed.