Mechanical properties of membrane surface of cultured astrocyte revealed by atomic force microscopy

In order to examine the mechanical properties of the membrane surface of as trocytes, we observed living astrocytes by atomic force microscopy (AFM) bo th in contact mode and force-mapping mode. Ridge-like structures reflecting actin filaments were observed in the topographic images in contact mode, b ut not in force-mapping mode, using a zero-loading force. When we measured the elasticity of astrocytes, we observed that the cell membrane above the nucleus was soft and the cell membrane above the cytosol was stiff. In part icular, the parts reflecting actin filaments were very stiff. This effect o f actin filaments on the elasticity of astrocytes was confirmed by the loss of actin filaments after application of actin-polymerization inhibitor.