Effects of bradykinin on cell volume and intracellular pH in NIH 3T3 fibroblasts expressing the ras oncogene

FEBS Letters

Lang, F.³  Wöll, E.¹  Häussinger, D.²  Ritter, M.¹ 

[1] Institut für Physiologie der Universität Innsbruck, Fritz-Pregl-Str. 3, A-6010 Innsbruck, Austria;Medizinische Klinik der Universitat Freiburg, Hugstetterstr. 55, D-7800 Freiburg, Germany;Physiologische Institut der Universität tübingen, Gmelinstr. 5, D-7400 Tübingen, Germany

关键词: Intracellular pH;    Na+/H+-exchanger;    Cell volume;    Ras oncogene;    Bradykinin;   

DOI  :  10.1016/0014-5793(92)80714-R

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

BCECF fluorescence has been applied to determine intracellular pH (pH_i) in NIH 3T3 fibroblasts expressing the Ha-ras oncogene (+ras) and otherwise identical cells not expressing the oncogene (−ras). In +ras cells, pH_i is significantly more alkaline (6.79 ± 0.03 n = 12) than in −ras cells (6.64 ± 0.02, n = 8). Bradykinin (100 nmol/1) leads to intracellular alkalinization in both +ras (to 6.96 ± 0.04, n = 12) and −ras cells (to 6.85 ± 0.02, n = 8). The effect or bradykinin is completely abolished in the presence of dimelhylamiloride (100μmol/1), which does not modify pH_i in the absence or bradykinin. Similar to bradykinin, cell shrinkage by addition of 15 mmol/1 NaCl to the extracellular fluid leads to intracellular alkalinization (by 0.08 ± 0.01, n = 15). Cell volume is significantly greater in +ras cells (2.7 ± 0.4 pl, n = 15) than in −ras calls (2.2 ± 0.4 pl, n = 15), Bradykinin leads to cell shrinkage in both +ras cells (by 7 ± 1%, n = 17) and −ras cells (by 5 ± 1%, n = 15). The effect of bradykinin on cell volume can be reversed by the reduction or extracellular NaCl concentration by 15 mmol/1 NaCl in +ras cells and by 7 mmol/1 NaCl in −rus cells. This maneuver completely abolishes (in −ras cells) or blunts (in +ras cells) the alkalinizing effect of bradykinin. In conclusion, +ras cells are more alkaline than −ras cells. Bradykinin leads to further intracellular alkalinization by activation of the Na⁺/H⁺-exchanger, at least in part secondary to hormone-induced cell shrinkage.

【 授权许可】

Unknown