Background chloride currents in fetal human nasopharyngeal epithelial cells.
- Author:
Xue-Rong SUN
1
;
Li-Wei WANG
;
Jian-Wen MAO
;
Lin-Yan ZHU
;
Si-Huai NIE
;
Ping ZHONG
;
Li-Xin CHEN
Author Information
1. Laboratory of Physiology, Guangdong Medical College, Zhanjiang 524023, China.
- Publication Type:Journal Article
- MeSH:
Cells, Cultured;
Chloride Channels;
antagonists & inhibitors;
physiology;
Electrophysiology;
Epithelial Cells;
cytology;
metabolism;
physiology;
Fetus;
Humans;
Nasopharynx;
cytology;
Nitrobenzoates;
pharmacology;
Patch-Clamp Techniques;
Tamoxifen;
pharmacology
- From:
Acta Physiologica Sinica
2005;57(3):349-354
- CountryChina
- Language:Chinese
-
Abstract:
To characterize the background current in fetal human nasopharyngeal epithelial cells and clarify its relationship with volume activated Cl(-) currents (I(Cl,vol)), whole-cell patch clamp and cell imaging techniques were employed. Under isotonic conditions, a background current [(5.9+/-2.1) pA/pF at +80 mV, n=21] was detected. The current presented a weak outward rectification and a negligible time-dependent inactivation. The current-voltage relationship showed that the reversal potential of the background current [(-0.73+/-1.7) mV, n=21] was close to the calculated equilibrium potential for Cl(-)(-0.9 mV). Application of extracellular hypertonic stimulation (440 mOsmol/L) suppressed the current by (59.6+/-7.1)% and the inhibition was reversible after returned to isotonic conditions. Bathing the cells in hypotonic solution (160 mOsmol/L) induced a volume-sensitive Cl(-) current. The Cl(-) channel blockers, tamoxifen (20 micromol/L) and 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) (100 micromol/L), inhibited the background current by (74.0+/-5.2)% (P<0.01, n=5) and (60.9+/-8.9)% (P<0.01, n=6) at +80 mV and increased basal cell volume by (107.7+/-2.9)% (P<0.01, n=25) and (104.4+/-2.4)% (P<0.01, n=19), respectively. The data indicate that Cl(-) current is an important component of the background current in fetal human nasopharyngeal epithelial cells. The background Cl(-) current is involved in volume activated Cl(-) current and basal cell volume regulation.
