Abstract
Circumstantial evidence of store operated channels (SOCs) has been accumulated in exocrine acinar cells. After depletion of internal Ca storage pools with strong agonist stimulations or with a SERCA pump inhibitor, thapsigargin, Ca-influx from the external milieu induces a substantial part of cytosolic Ca-increases. However, no direct measurement of SOCs has been carried out in the acinar cells. The foreground channel currents of the acinar cells, sensitive to an increase in cytosilic Ca, make the assessment of SOC current not easy. Eliminating the foreground currents with large size cation and anion, we successfully detected divalent cation currents after the store depletion in whole-cell patch-clamp recordings from rat pancreatic acinar cells. The peak magnitude of the divalent cation currents reached the order of tens pico-amperes and seemingly inactivated at negative membrane potentials during the time course. The divalent currents may play a role as a route of capacitative Ca entries in pancreatic Ca signaling. [Jpn J Physiol 54 Suppl:S48 (2004)]
