Pieri C, Recchioni R, Moroni F, Balkay L, Márián T, Trón L, Damjanovich S
Dipartimento di Richerche Gerontologiche e Geriatriche, Sezione Italiana, (V.I.L.E.G.), I.N.R.C.A., Ancona.
Biochem Biophys Res Commun. 1989 May 15;160(3):999-1002. doi: 10.1016/s0006-291x(89)80100-7.
Bretylium tosylate - a sodium channel opener - resulted in an increase of membrane potential of depolarized human, rat and mouse T and B lymphocytes. Flow cytometric membrane potential measurements with bis-oxonol revealed that the above hyperpolarizing effect was amiloride, ouabain, tetrodotoxin, azide and temperature sensitive. The effect showed an absolute dependence on the extracellular sodium but it was insensitive to the extracellular Ca2+ level. The voltage gating of the effect can be eliminated by either an increase of the extracellular potassium concentration or low doses of veratrin. The existence of a voltage and ligand gated sodium channel is suggested in the plasma membrane of all kinds of lymphocytes. The hyperpolarization is explained by an increased activity of the electrogenic sodium-potassium ATP-ase. Induced opening of such sodium channels may regulate the electrogenic pump activity and indirectly cell activation.
甲苯磺酸溴苄铵——一种钠通道开放剂——导致去极化的人、大鼠和小鼠T淋巴细胞及B淋巴细胞的膜电位升高。用双苯甲酰亚胺进行的流式细胞术膜电位测量显示，上述超极化效应对氨氯吡咪、哇巴因、河豚毒素、叠氮化物和温度敏感。该效应绝对依赖细胞外钠，但对细胞外Ca2+水平不敏感。增加细胞外钾浓度或低剂量藜芦碱可消除该效应的电压门控。提示在各类淋巴细胞的质膜中存在电压门控和配体门控钠通道。超极化是由电生性钠钾ATP酶活性增加所解释。此类钠通道的诱导开放可能调节电生性泵的活性并间接调节细胞活化。
