title: Effects of ammonium chloride on membrane currents of acinar cells dispersed from the rat parotid gland.
abstract: In acinar cells freshly dispersed from rat parotid glands, the effects of ammonium chloride (NH4Cl) on membrane currents were studied using the whole-cell clamp method. When membrane currents were recorded with command pulses to 0 mV, applied at 2-s intervals from a holding potential of -70 mV, NH4Cl (5-20 mM) transiently decreased outward currents and then slowly increased both outward and inward currents. After reaching a peak in about 40-50 s, both outward and inward currents gradually decreased in the presence of NH4Cl and, on its wash-out, the currents returned to the control level. Butyrate (5-20 mM) had little effect on the resting membrane currents, but markedly inhibited the response to NH4Cl. Tetraethylammonium (5 mM) strongly reduced both the resting and NH4Cl-induced outward currents, whereas it slightly potentiated the NH4Cl-induced inward current without affecting the membrane current at the holding potential. Without ATP in the patch pipettes, carbachol-induced membrane currents were relatively resistant to Ca2+ removal from the external medium, but NH4Cl-induced currents were quickly abolished in the absence of Ca2+. We conclude that intracellular alkalinization with NH4Cl increases Ca2+ influx and activates Ca(2+)-dependent outward K+ and inward Cl- currents.
authors.affiliation: Department of Oral Surgery, School of Medicine, Nagoya University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Hayashi
authors.forename: T
authors.initials: T
authors.lastname: Shigetomi
authors.forename: M
authors.initials: M
authors.lastname: Ueda
authors.forename: T
authors.initials: T
authors.lastname: Kaneda
authors.forename: T
authors.initials: T
authors.lastname: Matsumoto
authors.forename: H
authors.initials: H
authors.lastname: Tokuno
authors.forename: T
authors.initials: T
authors.lastname: Tomita
mesh_terms: D000643:Ammonium Chloride / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002217:Carbachol / Q000494:pharmacology; D002462:Cell Membrane / Q000187:drug effects* / Q000502:physiology; D004553:Electric Conductivity; D005260:Female; D010306:Parotid Gland / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D000643:Ammonium Chloride; D002217:Carbachol; D002118:Calcium