Rouzaire-Dubois B, Bostel S, Dubois J M
Laboratoire de Neurobiologie cellulaire et moléculaire, CNRS, Gif-sur-Yvette, France.
Neuroscience. 1999 Jan;88(1):307-17. doi: 10.1016/s0306-4522(98)00236-x.
Volumes of neuroblastoma x glioma hybrid NG 108-15 cells were electronically measured in order to characterize the mechanisms involved in volume regulation in isosmotic and anisosmotic conditions. The cells behave as perfect osmometers when tonicity was changed at constant chloride concentration by adding sucrose or replacing NaCl with CaCl2 or MgCl2. In contrast, the cell volume was poorly dependent on tonicity when the Cl- concentration was changed by adding NaCl or H2O. Cell shrinkage was induced by cell stirring or after a hypotonicity-induced swelling. These volume decreases were abolished by caffeine but not by ryanodine or EGTA. Shrinkage was also induced by the Ca2+ ionophore ionomycin. The ionomycin-induced volume decrease was abolished by EGTA. Cell swelling induced an outwardly rectifying Cl- current which was blocked by 5-nitro-2-(3-phenylpropylamino)benzoic acid, 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid and dihydroindenyloxy-alkanoic acid. When the tonicity was reduced at constant Cl- concentration by replacing NaCl with CaCl2 or MgCl2, the volume increased and then slowly decreased towards its control value. This regulatory volume decrease was blocked by 5-nitro-2-(3-phenylpropylamino)benzoic acid, 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid and dihydroindenyl-oxy-alkanoic acid. Long-term (hours-days) cell shrinkage was induced by a reduction of the culture medium osmolarity. Long-term cell swelling was induced by an increase of the culture medium osmolarity. These volume changes were abolished by the protein translation inhibitor cycloheximide. The results suggest that NG 108-15 cell volume is regulated by at least four interacting mechanisms controlled, respectively, by intracellular Ca2+, extracellular NaCl, cell volume and intracellular ionic strength. The speculative nature of ionic systems responsible for these volume regulating mechanisms is discussed.
为了描述等渗和非等渗条件下体积调节所涉及的机制，对神经母细胞瘤x胶质瘤杂交细胞NG 108 - 15进行了电子体积测量。当通过添加蔗糖或将NaCl替换为CaCl2或MgCl2在恒定氯离子浓度下改变张力时，细胞表现为完美的渗透计。相反，当通过添加NaCl或H2O改变Cl-浓度时，细胞体积对张力的依赖性很差。细胞搅拌或低渗诱导肿胀后会引起细胞收缩。这些体积减小被咖啡因消除，但不被ryanodine或EGTA消除。Ca2+离子载体ionomycin也可诱导收缩。EGTA消除了ionomycin诱导的体积减小。细胞肿胀诱导了外向整流Cl-电流，该电流被5-硝基-2-(3-苯丙基氨基)苯甲酸、4,4'-二异硫氰酸根合芪-2,2'-二磺酸和二氢茚氧基链烷酸阻断。当通过将NaCl替换为CaCl2或MgCl2在恒定Cl-浓度下降低张力时，体积增加，然后缓慢降至其对照值。这种调节性体积减小被5-硝基-2-(3-苯丙基氨基)苯甲酸、4,4'-二异硫氰酸根合芪-2,2'-二磺酸和二氢茚基氧基链烷酸阻断。培养基渗透压降低会诱导长期（数小时至数天）的细胞收缩。培养基渗透压升高会诱导长期的细胞肿胀。这些体积变化被蛋白质翻译抑制剂环己酰亚胺消除。结果表明，NG 108 - 15细胞体积受至少四种相互作用机制调节，分别由细胞内Ca2+、细胞外NaCl、细胞体积和细胞内离子强度控制。讨论了负责这些体积调节机制的离子系统的推测性质。
