Acetylcholine stimulates a Ca2+-dependent Cl− conductance in mouse lacrimal acinar cells

Patch-clamp whole-cell current recordings under voltage-clamp conditions were carried out on isolated mouse exorbital lacrimal acinar cells. Acetylcholine evoked outward current at a membrane potential of –20 mV whereas an inward current was observed at –80 mV. The outward current is due to the well-known calcium-activated K⁺ channels whereas the inward current was Cl^– dependent. The acetylcholine-evoked Cl^– current was abolished when the intracellular Ca²⁺ concentration was clamped at very low levels by a high intracellular EGTA concentration. Acetylcholine therefore activates a Ca²⁺-dependent Cl^– conductance in mouse lacrimal acinar cells.