Modulation of CCK-8-evoked intracellular Ca2+ waves by hydrogen peroxide in mouse pancreatic acinar cells

In the present study we have employed single cell imaging analysis to monitor the propagation of cholecystokinin-evoked Call waves in mouse pancreatic acinar cells. Stimulation of cells with 1 nM CCK-8 led to an initial Ca2+ release at the luminal cell pole and subsequent spreading of the Ca2+ signal towards the basolateral membrane in the form of a Call wave. Inhibition of sarcoendoplasmic reticulum Ca2+-ATPase (SERCA) activity by 1 mu M thapsigargin, preincubation in the presence of 100 mu M H2O2 or inhibition of PKC with either 5 mu M Ro31-8220 or 3 mu M GF-109203-X all led to a faster propagation of CCK-8-induced Ca2+ signals. The propagation of CCK-8-evoked Ca2+ signals was slowed down by activation of PKC with 1 mu M PMA, and preincubation of cells in the presence of H2O2 counteracted the effect of PKC inhibition. The protonophore FCCP (100 nM) and the inhibitor of the mitochondrial Ca2+-uniporter Ru360 (10 mu M) led to an increase in the propagation rate of CCK-8-evoked Ca2+ waves. Finally, depolymerisation of actin cytoskeleton with cytochalasin D (10 mu M) led to a faster propagation of CCK-8-evoked Ca2+ signals. Stabilization of actin cytoskeleton with jasplakinolide (10 mu M) did not induce significant changes on CCK-8-evoked Ca2+ waves. Preincubation of cells in the presence of H2O2 counteracted the effect of cytochalasin D on CCK-8-evoked Ca2+ wave propagation. Our results suggest that spreading of cytosolic Ca2+ waves evoked by CCK-8 can be modulated by low levels of oxidants acting on multiple Ca2+ handling mechanisms.