HepG2 cells were treated with bovine serum albumin (Con or (−)), PA (500 μM), PA+verapamil (Ver, 50 μM) or PA+nicardipine (Nic, 100 μM) for 9 h. (a-d) After each treatment, cells were loaded with a calcium indicator X-Rhod-1-AM (a,b) or Fura-2-AM (c,d). Calcium levels were visualized by laser confocal microscopy (a) or by dual fluorescent microscopy (c, 340/380 nm ratio image) and quantified (b,d; n=8 and 30, respectively). 