Abstract
SUMMARY: The reactions of XTH‐2 cells (line derived from Xenopus laevis tadpole hearts) to cytochalasin D (CD) were followed using scanning acoustic microscopy (SAM) at 0.9 GHz, fluorescence and electron microscopy. The first reaction to CD which can be detected by SAM is a loss of image contrast, indicating a decrease in acoustic impedance of about 30%. Based on structural changes revealed by staining of actin with TRITC‐phalloidin, and taking theoretical considerations into account, a relationship between impedance decrease and tension in the actin fibrillar system is deduced.