AMILORIDE-SENSITIVE SODIUM CONDUCTANCE IN HUMAN B-LYMPHOID CELLS

被引:44
作者
BUBIEN, JK
WARNOCK, DG
机构
[1] UNIV ALABAMA, DIV NEPHROL, BIRMINGHAM, AL 35294 USA
[2] UNIV ALABAMA, DEPT VET AFFAIRS MED CTR, BIRMINGHAM, AL 35294 USA
来源
AMERICAN JOURNAL OF PHYSIOLOGY | 1993年 / 265卷 / 04期
关键词
SODIUM ION CHANNELS; VOLTAGE CLAMP; ADENOSINE; 3'; 5'-CYCLIC MONOPHOSPHATE;
D O I
10.1152/ajpcell.1993.265.4.C1175
中图分类号
Q4 [生理学];
学科分类号
071003 ;
摘要
The Na+ conductance of RPMI 1640 and the pipette solution cells was examined using whole cell patch clamp. When the bath solution contained RPMI 1640 and the pipette solution contained (in mM) 100 potassium gluconate, 30 KCl, 10 NaCl, 0.5 ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA). and 20 N-2-hydroxythylpiperazine-N'-2-ethanesulfonic acid (HEPES), as well as well as <10 nM free Ca2+, pH 7.25, the mean membrane potential was -58 +/- 4.5 mV (n = 18). Cells were voltage clamped from -160 to +40 mV in 20-mV increments. The inward conductance was 767 +/- 221 pS/10 pF, and the outward conductance was 1,212 +/- 272 pS/10 pF (n = 12). Superfusion with 2 muM amiloride significantly hyperpolarized the cells by 7.4 +/- 2.2 mV (P = 0.004), significantly reduced the inward conductance to 221 +/- 65 pS/10 pF (P = 0.028), but had no effect on the outward conductance (1.294 +/- 236 pS/10 pF, P = 0.820, after amiloride). Next, the pipette and bath solutions were changed to (in mM) 150 sodium gluconate, 0.5 EGTA, and 20 HEPES, as well as <10 nM free Ca2+, pH 7.25. Under these conditions amiloride significantly reduced (50%, P < 0.05; n = 7) the whole cell currents. When potassium gluconate was substituted for sodium gluconate, amiloride had no effect. Thus amiloride inhibited a Na+-specific conductance expressed by B lymphoid cells. Benzamil is also a potent inhibitor of Na+ conductance in B lymphoid cells (50% inhibitory concentration = 10 nM; n = 4); however, dimethyl amiloride and ethylisopropyl amiloride (2 muM) had no effect. 8-(4-Chlorophenylthio) adenosine 3',5'-cyclic monophosphate (400 muM) specifically increased inward Na+ conductance, which was completely and reversibly inhibited by 2 muM amiloride. The properties of the amiloride-sensitive component of the Na+ conductance expressed by human B lymphoid cells are indistinguishable from those expressed in the apical membranes of epithelial cells.
引用
收藏
页码:C1175 / C1183
页数:9
相关论文
共 35 条
  • [1] AMILORIDE - A MOLECULAR PROBE OF SODIUM-TRANSPORT IN TISSUES AND CELLS
    BENOS, DJ
    [J]. AMERICAN JOURNAL OF PHYSIOLOGY, 1982, 242 (03): : C131 - C145
  • [2] ELEVATION OF INTRACELLULAR CALCIUM REDUCES VOLTAGE-DEPENDENT POTASSIUM CONDUCTANCE IN HUMAN T-CELLS
    BREGESTOVSKI, P
    REDKOZUBOV, A
    ALEXEEV, A
    [J]. NATURE, 1986, 319 (6056) : 776 - 778
  • [3] BRENT LH, 1990, J IMMUNOL, V145, P2381
  • [4] INHIBITION OF COLONIC NA+ TRANSPORT BY AMILORIDE ANALOGS
    BRIDGES, RJ
    CRAGOE, EJ
    FRIZZELL, RA
    BENOS, DJ
    [J]. AMERICAN JOURNAL OF PHYSIOLOGY, 1989, 256 (01): : C67 - C74
  • [5] CELL-CYCLE DEPENDENCE OF CHLORIDE PERMEABILITY IN NORMAL AND CYSTIC-FIBROSIS LYMPHOCYTES
    BUBIEN, JK
    KIRK, KL
    RADO, TA
    FRIZZELL, RA
    [J]. SCIENCE, 1990, 248 (4961) : 1416 - 1419
  • [6] BUBIEN JK, 1992, J AM SOC NEPHROL, V3, pA557
  • [7] BUBIEN JK, IN PRESS J CELL BIOL
  • [8] Cahalan M D, 1990, Semin Immunol, V2, P107
  • [9] A CAMP-REGULATED CHLORIDE CHANNEL IN LYMPHOCYTES THAT IS AFFECTED IN CYSTIC-FIBROSIS
    CHEN, JH
    SCHULMAN, H
    GARDNER, P
    [J]. SCIENCE, 1989, 243 (4891) : 657 - 660
  • [10] CYCLIC-AMP MODULATED POTASSIUM CHANNELS IN MURINE B-CELLS AND THEIR PRECURSORS
    CHOQUET, D
    SARTHOU, P
    PRIMI, D
    CAZENAVE, PA
    KORN, H
    [J]. SCIENCE, 1987, 235 (4793) : 1211 - 1214