Chloride transport mechanism in swine tracheal submucosal gland cells.
To clarify the mechanism for Cl- transport in swine tracheal submucosal gland cells, we measured chloride (Cl-) flux by means of a Cl(-)-sensitive fluorophore, 6-methoxy-N-(3-sulfopropyl)quinolinium (SPQ). An abrupt change of Cl(-)-free bath to a Cl(-)-containing (114 mM) solution induced the Cl- influx into the cells at a rate of 0.52 mM/s (p < 0.05). Removal of sodium (Na+) and the addition of 0.5 mM furosemide significantly reduced the rate of gradient-induced Cl- influx to 0.21 (p < 0.05) and 0.19 mM/s (p < 0.05), respectively. In gland tissue treated with 0.1 mM ouabain, the removal of external potassium (K+) in the presence of 5 mM barium significantly reduced the rate of Cl- influx to 0.21 mM/s (p < 0.05). An abrupt change from a Cl(-)-containing bath to a Cl(-)-free solution induced the Cl- efflux from the cells at a rate of 0.10 mM/s (p < 0.05). Acetylcholine increased the rate of gradient-induced Cl- efflux in a dose-dependent manner to 0.78 mM/s at 10(-6) M. This effect of acetylcholine was significantly diminished by diphenylamine-2-carboxylic acid (DPC, 10(-9) M), a Cl- channel blocker (p < 0.05). Isoproterenol (10(-5) M) had no effect on the Cl- efflux. These findings indicate that a Na-K-Cl co-transporter plays a major role in Cl- entry, and that Cl- efflux was activated by cholinergic receptor stimulation, but not by beta-adrenergic stimulation, via a DPC-inhibitable Cl- channel.
Nishikawa
K
K
Second Department of Internal Medicine, Yamanashi Medical University, Japan.
Ishihara
H
H
Ozawa
K
K
Tamura
K
K
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D018118:Chloride Channels / Q000187:drug effects / Q000378:metabolism*; D002712:Chlorides / Q000378:metabolism*; D005453:Fluorescence; D005456:Fluorescent Dyes; D017136:Ion Transport / Q000187:drug effects; D009092:Mucous Membrane / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D011806:Quinolinium Compounds; D013552:Swine; D014132:Trachea / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D062367:ortho-Aminobenzoates / Q000494:pharmacology
D002121:Calcium Channel Blockers; D018118:Chloride Channels; D002712:Chlorides; D005456:Fluorescent Dyes; D011806:Quinolinium Compounds; D062367:ortho-Aminobenzoates; C052335:6-methoxy-N-(3-sulfopropyl)quinolinium; C001209:fenamic acid; D000109:Acetylcholine