The properties of the secretagogue-evoked chloride current in mouse pancreatic acinar cells

In this paper we describe the properties of the secretagogue-evoked chloride current from mouse pancreatic acinar cells. Single cells were patch-clamped in the whole-cell configuration with solutions that excluded cation currents and then stimulated with 1 mM carbachol (CCh). This resulted in a current that rose to a peak and then decayed to a plateau level. The current/voltage relationship of the peak current was linear whereas that of the plateau phase was rectified and showed time and voltage dependence. To determine if the CCh evoked current was strictly Ca2+ dependent, we compared the properties of the plateau current with those of currents evoked by directly raising cytosolic [Ca2+]. The properties of the two currents were the same, with both currents showing outward rectification, development at depolarised potentials, similar time constants of activation, permeability sequences and sensitivity to the Cl– channel inhibitor 4,4′-diisothiocyanatodihydrostilbene-2,2′-disulphonic acid (DIDS). We conclude that the agonist-evoked rise in Ca2+ is alone a sufficient signal to activate the CL– current.