Acetylcholine-induced change in intracellular Cl? activity of the mouse lacrimal acinar cells

Abstract

Using double-barreled Cl⁻-sensitive microelectrodes, intracellular Cl⁻ activity (A _Cl ⁱ ) in the mouse lacrimal acinar cells in vitro was determined in both resting and secretory phases. In the resting stateA _Cl ⁱ was 31 mmol/l which was 1.4 times higher than that predicted for the passive distribution according to the membrane potential (V_m) of −41 mV. Addition of acetylcholine (ACh, 1μM) hyperpolarizedV_m to −63 mV and decreasedA _Cl ⁱ to 20 mmol/l which was still twice the equilibrium activity. A-23178 produced similar changes inV_m andA _Cl ⁱ to those induced by ACh. It was concluded that Cl⁻ was actively accumulated in the acinar cells and, in the secretory phase, Cl⁻ efflux was enhanced by the increased driving force and Ca²⁺-mediated increase in the Cl⁻ permeability across the cell membrane.