Fig. 7. Inhibitors of vesicular traffic abolish the pH buffering capability of preconditioned hepatocytes. Isolated hepatocytes were loaded with a pH fluorescence indicator (see Materials and Methods for details) and then incubated under control or hypoxic conditions. Two sets of preconditioned hepatocytes were prepared, either by hypoxic-reoxygenation cycle (PC) or by incubation for 15 minutes with 1 µM CGS21680 (CGS). In some samples incubation were performed in the presence of 250 nM WM, 10 mM 3MA or 20 µM Cyt D. Panel A shows that WM, 3MA and Cyt D did not affect the pHi of hepatocytes incubated under control or hypoxic conditions. These drugs, however, abolished the pH buffering effect associated with hypoxic- or CGS21680-induced preconditioning (panels B and C, respectively). The results are means of three experiments ± s.d. (^*P<0.001, statistical significance vs hypoxia and PC or CGS incubated under hypoxia in the presence of inhibitors.)