Figure 3

Assessment of TK VI-induced [Ca²⁺] _c increases using confocal fluo-3 fluorescence imaging. (A)A23187 was a positive control for agitation of [Ca²⁺] _c . (B) and (C), HepG2 cells were loaded with Fluo-3 acetoxymethyl ester and treated with 10 and 20 μM TK VI or Alamethicin (ALam, a classical representative of peptaibols) diluted in PBS alone or containing 2 mM CaCl₂. Then cells were examined from 0 to 900 sec for Fluo-3 fluorescence intensity. Original trace of fluorescence intensity as a measure of [Ca²⁺] _c recorded from the cells was marked in the confocal images. TK VI-induced [Ca²⁺] _c increase was assessed by using confocal two-photon fluo-3 fluorescence imaging. (B: right panel and C: middle and right panel). Three cells responded to TK VI stimulation with an increase in fluo-3 fluorescence intensity were used as a measure of [Ca²⁺] _c (indicated with arrows). The graph was labeled with arabic numbers that referred to the images. The images of cells treated with TK VI and Alamethicin (10 μM) diluted in PBS alone were shown in left panels in B and C.