Fig. 5. (A) Histamine-induced impedance alteration of cells on the surface modified with only 1-aminohexa(ethylene oxide) monomethyl ether molecules (no RGD) after 3.5 h of plating the cells and before the fura-2 dye-loading procedure. This peak displayed a weakly visible change (less than 1%), with no initial immediate decrease on this surface. (B) Phase-contrast image of cells on this surface. These data further support the idea that a reduction in cell–cell adhesion precedes the immediate histamine-induced decrease in the impedance value.