SODIUM-PERMEABLE CHANNELS IN THE APICAL MEMBRANE OF HUMAN NASAL EPITHELIAL-CELLS

被引:35
作者
CHINET, TC [1 ]
FULLTON, JM [1 ]
YANKASKAS, JR [1 ]
BOUCHER, RC [1 ]
STUTTS, MJ [1 ]
机构
[1] UNIV N CAROLINA, SCH MED, CHAPEL HILL, NC 27599 USA
来源
AMERICAN JOURNAL OF PHYSIOLOGY | 1993年 / 265卷 / 04期
关键词
SODIUM CHANNELS; NONSELECTIVE CATION CHANNELS; PATCH CLAMP; AIRWAY EPITHELIAL CELLS; CYSTIC FIBROSIS;
D O I
10.1152/ajpcell.1993.265.4.C1050
中图分类号
Q4 [生理学];
学科分类号
071003 ;
摘要
We used patch-clamp techniques to study the channels that underlie the Na+ conductance of the apical membrane of human normal nasal epithelial cells. Cells were cultured on permeable supports and studied after confluence. In 172 of 334 (52%) excised membrane patches, we observed 20-pS Na+-permeable channels that do not discriminate between Na+ and K+ (pNa/pK = 1.33). These nonselective cation channels contained subpopulations that differed by dependence of open probability on voltage and bath Ca2+ activity, suggesting two or more channel types with similar electrical properties. In the presence of 10(-4) M amiloride in the pipette, the proportion of excised patches with nonselective cation channels decreased to 52 of 139 patches (37%), but the decrease was spread across all subpopulations of nonselective cation channels in excised patches. Thus no distinctive Na+-selective amiloride-sensitive channels were identified in excised patches. In cell-attached patches, Na+-permeable channels were recorded in 56 of 262 patches (21%). Their conductance was 21.4 +/- 1.5 pS (n = 25), and most were selective for Na+ over K+ (pNa/pK > 6). In the presence of amiloride (10(-4) M) in the pipette, the frequency of lambda Na+-permeable channels in cell-attached patches decreased to 8 of 134 patches (6%), revealing a population of Na--selective channels recorded in cell-attached patches that was inhibited by amiloride. We conclude that, in excised patches, Na+-permeable channels are nonselective for Na+ over K+ and <30% appear to be amiloride sensitive. In contrast, in cell-attached patches, most channels that conduct sodium are 1) selective for Na+ over K+ and 2) amiloride sensitive. Although we have not discovered the explanation for the discrepancy between cell-attached and excised patch data, we speculate that the channels recognized on cell account for the amiloride-sensitive Na+ conductance of the apical membrane, whereas the excision process alters the properties of the Na+-permeable channels and/or activate new channels.
引用
收藏
页码:C1050 / C1060
页数:11
相关论文
共 35 条
[1]   NA+ TRANSPORT IN CYSTIC-FIBROSIS RESPIRATORY EPITHELIA - ABNORMAL BASAL RATE AND RESPONSE TO ADENYLATE-CYCLASE ACTIVATION [J].
BOUCHER, RC ;
STUTTS, MJ ;
KNOWLES, MR ;
CANTLEY, L ;
GATZY, JT .
JOURNAL OF CLINICAL INVESTIGATION, 1986, 78 (05) :1245-1252
[2]   EVIDENCE FOR REDUCED CL- AND INCREASED NA+ PERMEABILITY IN CYSTIC-FIBROSIS HUMAN PRIMARY-CELL CULTURES [J].
BOUCHER, RC ;
COTTON, CU ;
GATZY, JT ;
KNOWLES, MR ;
YANKASKAS, JR .
JOURNAL OF PHYSIOLOGY-LONDON, 1988, 405 :77-103
[3]   LUNG-FUNCTION DECLINES IN PATIENTS WITH PULMONARY SARCOIDOSIS AND INCREASED RESPIRATORY EPITHELIAL PERMEABILITY TO TC-99M-DTPA [J].
CHINET, T ;
DUSSER, D ;
LABRUNE, S ;
COLLIGNON, MA ;
CHRETIEN, J ;
HUCHON, GJ .
AMERICAN REVIEW OF RESPIRATORY DISEASE, 1990, 141 (02) :445-449
[4]   CHARACTERIZATION OF A 25-PS NONSELECTIVE CATION CHANNEL IN A CULTURED SECRETORY EPITHELIAL-CELL LINE [J].
COOK, DI ;
PORONNIK, P ;
YOUNG, JA .
JOURNAL OF MEMBRANE BIOLOGY, 1990, 114 (01) :37-52
[5]   ABNORMAL APICAL CELL-MEMBRANE IN CYSTIC-FIBROSIS RESPIRATORY EPITHELIUM - AN INVITRO ELECTROPHYSIOLOGIC ANALYSIS [J].
COTTON, CU ;
STUTTS, MJ ;
KNOWLES, MR ;
GATZY, JT ;
BOUCHER, RC .
JOURNAL OF CLINICAL INVESTIGATION, 1987, 79 (01) :80-85
[6]   SINGLE-CHANNEL RECORDINGS FROM THE APICAL MEMBRANE OF THE TOAD URINARY-BLADDER EPITHELIAL-CELL [J].
FRINGS, S ;
PURVES, RD ;
MACKNIGHT, ADC .
JOURNAL OF MEMBRANE BIOLOGY, 1988, 106 (02) :157-172
[7]   ALTERED REGULATION OF AIRWAY EPITHELIAL-CELL CHLORIDE CHANNELS IN CYSTIC-FIBROSIS [J].
FRIZZELL, RA ;
RECHKEMMER, G ;
SHOEMAKER, RL .
SCIENCE, 1986, 233 (4763) :558-560
[8]   AMILORIDE-SENSITIVE TRYPSINIZATION OF APICAL SODIUM-CHANNELS - ANALYSIS OF HORMONAL-REGULATION OF SODIUM-TRANSPORT IN TOAD BLADDER [J].
GARTY, H ;
EDELMAN, IS .
JOURNAL OF GENERAL PHYSIOLOGY, 1983, 81 (06) :785-803
[9]   NA+ SELECTIVE CHANNELS IN THE APICAL MEMBRANE OF RABBIT LATE PROXIMAL TUBULES (PARS RECTA) [J].
GOGELEIN, H ;
GREGER, R .
PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY, 1986, 406 (02) :198-203
[10]  
HAMILTON KL, 1986, FASEB J, V45, P2713