SIMULTANEOUS DIGITAL IMAGING ANALYSIS OF CYTOSOLIC CALCIUM AND MORPHOLOGICAL CHANGE IN PLATELETS ACTIVATED BY SURFACE-CONTACT

The dynamic change of cytoplasmic Ca2+ concentration ([Ca2+](i)) and m orphological change were investigated simultaneously by confocal laser scanning microscopy using fluo-3 and by differential interference con trast optics in platelets activated by contact with the following type s of surfaces: native glass and glass treated with poly-L-lysine (PLL) , fibrinogen (Fg), or von Willebrand factor (vWF). The initial [Ca2+]( i) values just after the surface contact were comparable (approximatel y 100 nM) among platelets deposited on the four surface types. On the PLL-surface, no morphological change or [Ca2+](i) elevation was observ ed. Glass-, Fg-, and vWf-surface adhered platelets showed pseudopod fo rmation and spreading associated with the inhomogeneous [Ca2+](i) rise . The platelets on the Fg-surface were the most active in terms of [Ca 2+](i) rise and morphological change. During pseudopod formation, the mean [Ca2+](i) value was maximal and localized high [Ca2+](i) zones we re observed inside pseudopods, as well as in the center of the platele ts. After spreading, high [Ca2+](i) zones still remained in the center of the cell. This new technique enabled simultaneous observation of [ Ca2+](i) and cell shape and we clearly demonstrated a close relationsh ip between [Ca2+](i) and morphological alterations. (C) 1996 Wiley-Lis s, Inc.