Electron microscope study on the occurrence of electron-dense deposits at the cell membrane of chicken erythrocytes

Electron-dense deposits were found along the inner side of the cell membrane of chicken erythrocytes when fixed in a CaCl2-containing glutaraldehyde solution. Osteoblasts and osteoclasts were studied in an attempt to determine whether the deposits are related to calcium metabolism. No electron-dense deposits adjacent to the cell membrane were found in either these cells or in rat erythrocytes. Therefore, it is assumed that the deposits are not calcium-binding protein necessary for the cellular calcium uptake.