The Effect of Acetylcholine on Chloride Transport Across the Mouse Lacrimal Gland Acinar Cell Membranes

The mechanisms of Cl- transport and the effects of acetylcholine (ACh) and electrochemical Cl- potential changes across the basolateral plasma membrane on intracellular Cl- activity in the acinar cells of isolated mouse lacrimal glands were studied using double-barreled Cl- -selective microelectrodes. In the resting state, the basolateral membrane potential (Vm) was about -40 mV and intracellular Cl- activity was about 35 mmol/l. Addition of ACh (10(-9) approximately 10(-6) mol/l) hyperpolarized Vm and decreased the Cl- activity in a dose-dependent manner. ACh (10(-6) mol/l) hyperpolarized Vm by 20 mV and decreased the cytosolic Cl- activity with an initial rate of 16.0 mmol/l X min. Reduction of the perfusate Cl- concentration to 1/9 control depolarized Vm and decreased cytosolic Cl- activity at a rate of 1.9 mmol/l X min. A Vm hyperpolarization of 20 mV produced by DC injection to the adjacent cell decreased Cl- activity at a rate of 4.6 mmol/l X min. DIDS (1 mmol/l) hyperpolarized Vm by 8 mV with little change in Cl- activity and increased the input resistance of the cells by 25%. DIDS decreased the rate of change in Cl- activity induced by low-Cl- Ringer to 35% of control, but had no effect on the ACh-evoked decrease in the Cl- activity. Furosemide (1 mmol/l) slightly hyperpolarized Vm and decreased Cl- activity at a slow rate but affected Cl- movements induced by ACh or low-Cl- Ringer only slightly. Cl- uptake into the cells was inhibited partially by furosemide.(ABSTRACT TRUNCATED AT 250 WORDS)