FREE CYTOSOLIC CALCIUM LEVELS MODIFY INTRACELLULAR PH IN RAT PANCREATIC ACINI

We have used BCECF- or Fura-a-loaded rat pancreatic acinar cells to in vestigate the relationship between Ca2+ mobilization and intracellular pH (pH(i)). Ca2+-mobilizing agonists CCK-8 and ACh induced a transien t acidification totally dependent on release of Ca2+ from internal sto res. Employment of different physiological tools including ionomycin a nd thapsigargin to increase the cytosolic Ca2+ concentration and capac itative calcium influx also induced cellular acidification. Applicatio n of 1mM LaCl3 reduced the CCK-8-evoked acidification. These data indi cate that the mobilization of intracellular Ca2+ stores by CCK-8 decre ases cellular pH by Ca2+/H+ exchanger. (C) 1997 Academic Press