IONIC CURRENTS EVOKED BY ACETYLCHOLINE IN ISOLATED ACINAR-CELLS OF THE GUINEA-PIG NASAL GLAND

The patch-clamp whole cell recording was used to demonstrate activatio n of membrane conductance to K+, Cl- and cations induced by acetylchol ine (ACh) in the isolated acinar cells of the guinea pig nasal gland. A small outward K+ current at 0 mV and a large transient and sustained inward current at -90 mV were evoked by ACh and ACh-evoked reversal p otential was about -3 mV nearly to Cl- equilibrium potential in 140 mM KCl in the pipette and physiological saline in the bath. The ionic su bstitutional experiments indicated that ACh-evoked inward currents wer e carried by both Cl- and cations. Both outward and inward currents ev oked by ACh were almost completely abolished by removal of external Ca 2+ and mimicked those evoked by a calcium ionophore A23187. These find ings indicate that ACh-evoked membrane conductances are mediated by an increase in intracellular Ca2+. (C) 1994 Academic Press, Inc.