Amorino G P, Fox M H
Department of Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA.
J Membr Biol. 1996 Aug;152(3):217-22. doi: 10.1007/s002329900099.
Hyperthermia induces transient changes in [Na+]i and [K+]i in mammalian cells. Since Cl- flux is coupled with Na+ and K+ in several processes, including cell volume control, we have measured the effects of heat on [Cl-]i using the chloride indicator, MQAE, with flow cytometry. The mean basal level of [Cl-]i in Chinese hamster ovary cells was 12 mM. Cells heated at 42.0 degrees or 45.0 degrees C for 30 min had about a 2.5-fold increase in [Cl-]i above unheated control values when measured immediately after heating. There was about a 3-fold decrease in [Na+]i under the same conditions, as measured by Sodium Green. The magnitude of the increase in [Cl-]i depended upon time and temperature. The [Cl-]i recovered in a time-dependent fashion to control values by 30 min after heating. When cells were heated at 45.0 degrees C for 30 min in the presence of 1.5 mM furosemide, the heat-induced [Cl-]i increase was completely blocked. Since furosemide inhibits the Na+/K+/2Cl- cotransporter, Cl- channels, and even Cl-HCO3 exchange, these ion transporters may be involved in the heat-induced increase in [Cl-]i.
热疗可引起哺乳动物细胞内[Na⁺]i和[K⁺]i的短暂变化。由于在包括细胞体积调控在内的多个过程中，Cl⁻通量与Na⁺和K⁺相关联，我们使用氯离子指示剂MQAE，通过流式细胞术测量了热对[Cl⁻]i的影响。中国仓鼠卵巢细胞中[Cl⁻]i的平均基础水平为12 mM。在42.0℃或45.0℃加热30分钟的细胞，加热后立即测量时，其[Cl⁻]i比未加热的对照值增加了约2.5倍。通过Sodium Green测量，在相同条件下[Na⁺]i下降了约3倍。[Cl⁻]i增加的幅度取决于时间和温度。加热后30分钟内，[Cl⁻]i以时间依赖的方式恢复到对照值。当细胞在1.5 mM呋塞米存在的情况下于45.0℃加热30分钟时，热诱导的[Cl⁻]i增加被完全阻断。由于呋塞米抑制Na⁺/K⁺/2Cl⁻共转运体、Cl⁻通道甚至Cl⁻-HCO₃交换，这些离子转运体可能参与了热诱导的[Cl⁻]i增加。
