Fig. 6. Increase in InsP₃ receptor sensitivity induces coordination of Ca²⁺ oscillations in connected hepatocytes. Hepatocyte multiplets were loaded with fura2. Addition of a low concentration of noradrenaline (0.02 µM, A; 0.05 µM, B) for the time shown by the open box induced uncoordinated Ca²⁺ oscillations. However, when the same cells were incubated in the presence of 8Bromo-cAMP (10 µM, for the time shown by the black box; A), or when noradrenaline was perfused in the presence of thimerosal (10 µM, for the time shown by the black box; B), the same dose of noradrenaline elicited coordinated Ca²⁺ oscillations. The same results were obtained in hepatocyte doublets and are representative of those obtained using 7 triplets and 12 doublets in four independent experiments. For technical reasons, recording of the traces was interrupted during the washing process (3 minutes) and frame pairs were captured every 10 seconds during a part of thimerosal perfusion.